SQL Tools(JOIN Operator(Inner join, Left join, Right join))

INNER JOIN Operator :-
INNER Join return all rows from the join of left table and right table if there are same data available in both tables if no data will match then it will return null
SELECT * FROM Table_Name_1 INNER JOIN Table_Name_2 WHERE Table_Name_1.Column_Name = Table_Name_2.Column_Name

You can divide your result in group like :-
If a table contains First_Name, Last_Name, Address, Ph_No and there are so many result according to First_Name then you can use Group_By Like this :-

SELECT * FROM Old_Persons As OP INNER JOIN New_Persons As NP WHERE OP.First_Name = NP.First_Name Group By OP.First_Name

LEFT JOIN Operator :-
LEFT join return all rows from the left table even there are no rows in right table.

SELECT * FROM Old_Persons As OP LEFT JOIN New_Persons As NP WHERE OP.First_Name = NP.First_Name Group By OP.First_Name

RIGHT JOIN Operator :-
RIGHT JOIN return all rows from the right table even if there are no rows available in left table.

SELECT * FROM Old_Persons As OP RIGHT JOIN New_Persons As NP WHERE OP.First_Name = NP.First_Name Group By OP.First_Name

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SQL Tools(Alias Operator & In Operator)

ALIAS Name for Column :-
SELECT Column_Name AS Alias_Name FROM Table_Name

ALIAS Name for table :-
SELECT Column_Name From Table_Name AS Alias_Name

ALIAS Example :-
SELECT p.FirstName,p.LastName, po.OrderID
FROM Persons AS p, Product AS po
WHERE p.FirstName='Saurabh' AND p.LastName='Singh' AND po.OrderID > 2

Without using AS
SELECT p.FirstName,p.LastName, po.OrderID
FROM Persons p, Product po
WHERE p.FirstName='Saurabh' AND p.LastName='Singh' AND po.OrderID > 2

IN Operator :-
If you want to select OrderID of between 2,3,4,5 then :-
SELECT p.FirstName,p.LastName, po.OrderID
FROM Persons p, Product po
WHERE p.FirstName='Saurabh' AND p.LastName='Singh' AND po.OrderID IN (2,3,4,5)

OR :-
SELECT * FROM Persons
WHERE FirstName IN ('Saurabh','Saanjh', 'vivek')

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SQL - Tools (BETWEEN Operator)

SELECT column_name(s) FROM table_name
WHERE column_name BETWEEN value1 AND value2

SELECT * FROM COILS WHERE COIL_NAME BETWEEN SomeValue1 AND SomeValue2

Between operator is like It will select a row where COIL_NAME has SomeValue1 . Value depends on database to database . Some database will select rows where COIL_NAME has SomeValue1 and where COIL_NAME has SomeValue2.

We can use NOT BETWEEN operator if you you dont want to select those values like :-
SELECT * FROM COILS WHERE COIL_NAME NOT BETWEEN SomeValue1 AND SomeValue2
This query will select a value where coil_name is not equal to SomeValue1 and SomeValue2.

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SQL - Tools(Top Clause AND Like Operator)

SELECT TOP 1 FROM Table_Name

This will select 1 row from table

SELECT TOP 1* FROM Table_Name (Select all columns of 1st row)
SELECT TOP 2* FROM Table_Name (Select first two rows of table)
SELECT TOP 50 PERCENT * FROM Table_Name (Select 50 % rows from table)

LIKE OPERATOR

SELECT column_name(s)
FROM table_name
WHERE column_name LIKE pattern

IF a column name CITY from Persons table contains Kanpur, Delhi , NewDelhi , Kannauj , Nagar values then If you want to select city name starts from K then :-

SELECT * FROM Persons
WHERE CITY LIKE 'k%'

this will retrieve Kanpur , Kannauj.

If you want to select city name ends from i then :-
SELECT * FROM Persons
WHERE CITY LIKE '%i'


IF you want to select a city which has particular format like Select a city which has 'elh' pattern
SELECT * FROM Persons
WHERE City LIKE '%elh%'

this will retrieve Delhi , NewDelhi.

If you dont want to select a city which has particular format like 'elh'

SELECT * FROM Persons
WHERE City NOT LIKE '%elh%'

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SQL - Tools ( INSERT,UPDATE and DELETE Statement)

INSERT INTO table_name
VALUES (value1, value2, value3,...)

IF a table Persons contains P_Id,LastName,FirstName,Address,City columns.If you want to insert values then :-
INSERT INTO Persons
VALUES (4,'Singh', 'Saurabh', 'Sector-23', 'Gurgaon')

IF NOT EXISTS (SELECT * FROM Persons WHERE P_Id = 4)
BEGIN
INSERT INTO Persons
VALUES (4,'Singh', 'Saurabh', 'Sector-23', 'Gurgaon')
END

By this way it will check firstly, if this p_id exist in the table then do not insert otherwise insert these values in the table.

Update statement :-
UPDATE table_name
SET column1=value, column2=value2,...
WHERE some_column=some_value

We use If not exist statement whether there is a need to update or not.

DELETE Statement :-
DELETE From table_name WHERE some_column=some_value
Note :- Never use Delete * use Delete tableName.*

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SQL - Tools(ORDER BY)

ORDER BY keyword is used for sorting suppose in a table there is a column named first_name.
If you want to show the result in ascending order then :-

SELECT * FROM Persons WHERE Age >= 25 GROUP BY first_name ASC

If you want to show the result in descending order then :-
SELECT * FROM Persons WHERE Age >= 25 GROUP BY first_name DESC

By default it is ascendeng . if we use like GROUP BY first_name then it sorts in ascending order.

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SQL - Tools (WHERE, AND, OR Clause)

Where clause is use for filtering like :-

SELECT * FROM table_name WHERE column_name (operator) value
(operator) :- =, >, <,! and more operators.

A Friends table contains firstName, secondName, address, phone_no and firstName values are :- saurabh, sandy, gaurav, somu, saurabh and address column values are :- kanpur, allahabad, delhi, kanpur, varanasi.

SELECT * FROM Friends WHERE firstName = 'Saurabh' AND address = 'kanpur'

This will select only first row because only first row satisfies WHERE condition

SELECT * FROM Friends WHERE firstName = 'Saurabh' OR address = 'kanpur'

This will select first row, fourth row and fifth row due to oR condition in where clause

Operators :-
< :- lessthan
> :- greaterthan
<= :- less than or equal to
>= :- greater than or equal to
<> :- not equal to
BETWEEN :- between an inclusive range
LIKE :- for search pattern
IN :- SEARCH for exact values like if i know values are 1987, 1989

Use of IN clause :-
EXAMPLE :- SELECT * FROM Friends WHERE year IN (1987, 1989)

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SQL - Tools....(SELECT Clause)

SELECT :-

SELECT * FROM TABLE_NAME this will select whole table

If Coils table contains 5 columns p_id, coil_no, coil_width, coil_length, coil_name.Then you have to select coil_width and coil_no like :-

SELECT coil_width, coil_length FROM Coils

If you have to select distinct columns from table like coil_name columns have ABCDE12, ABCD13, ABCD14, ABCD12, ABCD14 then you have to choose only distinct values :-

SELECT DISTINCT column_name FROM table_name
SELECT DISTINCT coil_name FROM coils

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Visual Studio .Net ShortCut keys

DecreaseFilterLevel : ALT + ,
IncreaseFilterLevel : ALT + .
GotoBrace : CTRL + ]
GotoBraceExtend : CTRL _ SHIFT + ]
LineEnd : END
LineEndExtendColumn : SHIFT + ALT + END
ToggleWordWrap : CTRL + E, CTRL + W
ScrollLineDown : CTRL + DOWN ARRAY
LineDownExtendColumn : SHIFT + ALT + DOWN ARRAY
WordDeleteToEnd : CTRL + DEL
CopyParameterTip : CTRL + SHIFT + ALT + C
WordDeleteToStart : CTRL + BACKSPACE
SelectCurrentWord : CTRL + W
ViewWhiteSpace : CTRL + R , CTRL + W
Commenting : CTRL + k , CTRL + C
Uncommenting : CTRL + K , CTRL + U

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How to implement a progressBar while opening a textFile in an application ?

Make a claas like this one to create ProgressBar :-
public class StatusProgressBar : ToolStripProgressBar
{
#region Private Fields

private static StatusProgressBar _instance = null;

#endregion

#region Constructor

private StatusProgressBar()
{
this.Style = ProgressBarStyle.Blocks;
this.Step = 1;
}

#endregion

#region Properties

///

/// Get Singleton instance of progressBar
///

public static StatusProgressBar Instance
{
get
{
if (_instance == null)
{
_instance = new StatusProgressBar();
}

return _instance;
}
}

#endregion
}

Now main issue how to increase the bar and how calculate the percentage then firstly i would say calculate numer of lines to be read or parsed in amy editor according to your application

public const char NEWLINE_CHARACTER = '\n';
string[] lines = t.Split(NEWLINE_CHARACTER);

This will perform for all the lines and lines will be incremented then progress bar will be increemented accordingly.
for (int lineIndex = 0; lineIndex < lines.Length; lineIndex++)
{
if (lineIndex % 2 == 0)
{
StatusProgressBar.Instance.PerformStep();
StatusProgressBar.Instance.ToolTipText = Convert.ToString((StatusProgressBar.Instance.Value / StatusProgressBar.Instance.Maximum) * 100) + "%";
}
}

Happy to code................

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What is Reference counting in COM ?

Reference counting is a memory management technique used to count how many times an object has a pointer referring to it. The first time it is created, the reference count is set to one. When the last reference to the object is nulled, the reference count is set to zero and the object is deleted.
Care must be exercised to prevent a context switch from changing the reference count at the time of deletion. In the methods that follow, the syntax is shortened to keep the scope of the discussion brief and manageable.

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What is COM ?

Microsoft’s COM is a technology for component software development. It is a binary standard which is language independent. DCOM is a distributed extension of COM.
Microsoft COM (Component Object Model) technology in the Microsoft Windows-family of Operating Systems enables software components to communicate. COM is used by developers to create re-usable software components, link components together to build applications, and take advantage of Windows services. COM objects can be created with a variety of programming languages. Object-oriented languages, such as C++, provide programming mechanisms that simplify the implementation of COM objects. The family of COM technologies includes COM+, Distributed COM (DCOM) and ActiveX® Controls.

Microsoft provides COM interfaces for many Windows application programming interfaces such as Direct Show, Media Foundation, Packaging API, Windows Animation Manager, Windows Portable Devices, and Microsoft Active Directory (AD).

COM is used in applications such as the Microsoft Office Family of products. For example COM OLE technology allows Word documents to dynamically link to data in Excel spreadsheets and COM Automation allows users to build scripts in their applications to perform repetitive tasks or control one application from another.

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How can we make Windows API calls in .NET?

Windows API call are not COM based and they are invoked through Platform Invoke Services.StringConversionType is for what type of conversion should take place. Either we can specify Unicode to convert all strings to Unicode values, or Auto to convert strings according to the .NET runtime rules.

There are few thumbrules to make API calls :-
1:- MethodName is the name of the API to call.
2:- DllName is the name of the DLL.
3:- Args are any arguments to the API call.
4:- Type is the return type of the API call.

partial class Form1 : Form
{
[DllImport(“Kernel32.dll”)]
static extern int Sleep(long dwMilliseconds);
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
MessageBox.Show(“Starting of 5000 ms...”);
Sleep(5000);
MessageBox.Show(“End of 5000 ms...”);
}
}
}

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ShFileOperation not working under Wista and Windows7.

I've used ShFileOperation for file operations but was facing some problems and i was not able to understand then i do googling and found the 'cause' of the problems with the SHFileOperation function in Vista . It turns out that this function is not thread safe under Vista. It works fine with earlier operating systems when used in a multi threading application.

Then i got to know about IFileOPeration interface in vista, you can say a replacement of ShFileOperation.

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How to convert 2d array to 1d array ?

Suppose you to insert or get the values from 1d array using 2d dimensions like :-
Insert value at (1,2) and the value is 5 then you have to find the logic to get the index :-
Firstly you have to know the size of 2d array here suppose :- (2x3)

int xPosition = 1;
int yPosition = 2;

3 is ySize of 2d array.
int 1dIndex = (3*xPosition)+ yPosition ;

Insert at this index or get from this index.

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How to convert 3d array to 1d array ?

Suppose you have to insert a value at (2,1,0) and the value is :-5
means firstly you have to find the index through (2,1,0) then you have to insert value 5 at that index .

Logic is :-
Firstly you must have to know the 3d array size suppose here is (3x2x3).
int xPosition = 2;
int yPosition = 1;
int zPosition = 0;

int indexOf1dArray = (xPosition *2*3) + ((yPosition * 3)+zPosition) ;

Using this insert the value at this index indexOf1dArray and if you have to get the value then again find index using this method and then find the value at this place.

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What is the difference between .ToString() and Convert.ToString() ?

int value = 3;
string stringConversion = value.ToString();
string stringConversion = Convert.ToString(value);

We can convert the integer “value ” using “value .ToString()” or “Convert.ToString”
The basic difference between them is “Convert” function handles NULLS .It handles null exception while “value .ToString()”does not it will throw a NULL reference exception error. So as good coding practice using “convert” is always safe.

Happy to code...

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Built-in Code Snippets (C#)

List of built in code snippets -

#if :- Creates a #if directive and a #endif directive.
#region :- Creates a #region directive and a #endregion directive.
~ :- Creates a destructor for the containing class.
checked :- Creates a checked block.
ctor :- Creates a constructor for the containing class.
cw :- Creates a call to Console.WriteLine.
for :- Creates a for loop.
forr :- Creates a for loop that decrements the loop variable after each iteration.
invoke :- Creates a block that safely invokes an event.
iterindex :- Creates a "named" iterator and indexer pair by using a nested class.
lock :- Creates a lock block.
mbox :- Creates a call to System.Windows.Forms.MessageBox.Show. You
may need to add a reference to System.Windows.Forms.dll.
prop :- Creates a automatic property
propg :- Creates a property declaration with only a "get" accessor and a backing field.
propfull : Creates a property with private field.
sim :- Creates a static int Main method declaration.
svm :- Creates a static void Main method declaration.
try :- Creates a try-catch block.
tryf :- Creates a try-finally block.
unsafe :- Creates an unsafe block.
unchecked :- Creates an unchecked block.

Happy to code.

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.Net Standard Date-Time-Format strings

Have a look on this image you will find very interesting i mentioned all the date-time format strings in this image.

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Message-Box refreshing issue

I have used many message boxes in my current application but in some places where i used list box,list there when i move messagebox then the back screen is looks like everything is removing or cleaning nothing just refreshing issue, then i look and sort out by sinety testing like i used listView.BeginUpdate(); before dialog box check when i used after it then it works fine. because this method is used to update listview without any flicker and refreshing but i used before dialog check thats why i was facing that problem.

Happy to code...

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How to collapse Environmental variables in a path using C# ?

Pass the path if there are environmental variables exist in the path then it will be collapsed into a valid path and return the valid path.
Constants :-
public const string PATH_SEPARATOR = @"\";
public const string ENVIROMENT_VARIABLE_FORMAT = "%{0}%";

public static string CollapseEnviromentVariables(string pathString)
{
string result = pathString;

if (string.IsNullOrEmpty(pathString) == false)
{
IDictionary environmentVariables = Environment.GetEnvironmentVariables();
Dictionary matchingEnv = new Dictionary();
bool isReplaceEnv = false;

foreach (DictionaryEntry environmentVariable in environmentVariables)
{
if ((pathString.Length >= ((string)environmentVariable.Value).Length) && (pathString.Contains((string)environmentVariable.Value)))
{
isReplaceEnv = false;

foreach (string matchingEnvEntry in matchingEnv.Keys)
{
if ((((string)matchingEnv[matchingEnvEntry]).Length <= ((string)environmentVariable.Value).Length) &&
((string)environmentVariable.Value).Contains((string)matchingEnv[matchingEnvEntry]))
{
matchingEnv.Remove(matchingEnvEntry);
matchingEnv.Add((string)environmentVariable.Key, (string)environmentVariable.Value);
isReplaceEnv = true;
break;
}
}

if (isReplaceEnv == false)
{
matchingEnv.Add((string)environmentVariable.Key, (string)environmentVariable.Value);
}
}
}

int matchingEnvIndex = 0;
int matchingEnvLength = 0;

foreach (string matchingEnvEntry in matchingEnv.Keys)
{
matchingEnvIndex = result.IndexOf(matchingEnv[matchingEnvEntry]);
matchingEnvLength = matchingEnv[matchingEnvEntry].Length;

//Replace environment variable only if environment variable value is enclosed by path seperators
//and matched value is found after replacing other variables.
if ((matchingEnvIndex > -1) &&
((matchingEnvIndex == 0) || (result[matchingEnvIndex - 1].ToString() == Constants.PATH_SEPARATOR)) &&
((matchingEnvIndex + matchingEnvLength == result.Length) || (result[matchingEnvIndex + matchingEnvLength].ToString() == Constants.PATH_SEPARATOR)))
{
result = result.Replace(matchingEnv[matchingEnvEntry], string.Format(Constants.ENVIROMENT_VARIABLE_FORMAT, matchingEnvEntry));
}
}
}
return result;
}

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How to allign multiple strings using seperator in C# ?

Constant file.public const char SYMBOL_SPACE_CHARACTER = ' ';

public static List AlignText(string[] strings, char seperator)
{
List formattedStringList = new List();
List ListOfCommaSeperatedStringsInLine = new List();
string[] commaSeperatedStringsArray = null;
List maxColumnWidthArray = new List();

//split strings into list of comma seperated array of strings and calculate maximum length of string array.
foreach (string str in strings)
{
commaSeperatedStringsArray = str.Split(seperator);

//remove all trailing and leading spaces.
for (int index = 0; index < commaSeperatedStringsArray.Length; ++index)
{
commaSeperatedStringsArray[index] = commaSeperatedStringsArray[index].Trim();

//initialize maximum characters in each column.
if (maxColumnWidthArray.Count > index)
{
maxColumnWidthArray[index] = (maxColumnWidthArray[index] < commaSeperatedStringsArray[index].Length) ? commaSeperatedStringsArray[index].Length : maxColumnWidthArray[index];
}
else
{
maxColumnWidthArray.Add(commaSeperatedStringsArray[index].Length);
}
}

ListOfCommaSeperatedStringsInLine.Add(commaSeperatedStringsArray);
}

StringBuilder formattedString = new StringBuilder();
int accumlativeMaxLength = 0;
int pad = 0;

//Insert spaces to align text and append in single line text.
foreach (string[] stringsInLine in ListOfCommaSeperatedStringsInLine)
{
formattedString.Append(stringsInLine[0]);
accumlativeMaxLength = maxColumnWidthArray[0];

for (int index = 1; index < maxColumnWidthArray.Count; ++index)
{
if (stringsInLine.Length > index)
{
pad = accumlativeMaxLength - formattedString.Length;
formattedString.Append(seperator);
formattedString.Append(Constants.SYMBOL_SPACE_CHARACTER, pad);

if (IsNumeric(stringsInLine[index]))
{
formattedString.Append(Constants.SYMBOL_SPACE_CHARACTER, maxColumnWidthArray[index] - stringsInLine[index].Length);
}

formattedString.Append(stringsInLine[index]);
accumlativeMaxLength += maxColumnWidthArray[index] + 1;
}
}

formattedStringList.Add(formattedString.ToString());
formattedString.Length = 0;
}

return formattedStringList;
}
This is very useful method when you have to align certain strings and there is a seperator then this method will allign all the lines, just pass the array of strings and a seperator.

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How to check invalid characters in path using C#

If you create a new folder then there are some characters which are not allowed and any thing in which user have rights to create path then firstly check the invalid characters otherwise your application or program will through an exception.

Pass the path or string for which you have to check.
public static bool CheckInvalidCharacters(string path)
{
bool invalidCharacters = false;

if (string.IsNullOrEmpty(path) == false)
{
char[] invalidChars = Path.GetInvalidFileNameChars();

foreach (char invalidChar in invalidChars)
{
if (path.Contains(invalidChar.ToString()))
{
invalidCharacters = true;
break;
}
}
}
return invalidCharacters;
}
This will return a bool variable if path or string contains invalid characters then it will return true else false.

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Delegates in C#

Event - Delegates are the key feature of C#,You can say heart of C#.Look on a example :- Suppose if you have two forms and there is no communication between those even you can't create object to access then how will you send some information.In this tutorial i will teach you how to handle and play with delegates to proper communication.

Suppose you have to pass the multiple file paths to different forms and they are in different solutions or different forms :-
Step.1 :-
Make a class which will contain all the file path like this :-

public class FileOpenEventArgs : EventArgs
{
#region Private Fields

private string [] _filePath;

#endregion

#region properties

///

/// Sets/Gets the path of files.
///

public string [] FilePath
{
get
{
return _filePath;
}
set
{
_filePath = value;
}
}

#endregion
}

step.2 :- Now come to form from you have to pass the information
Declare a delegate and event like :-

public delegate void FileOpenHandler(object sender, FileOpenEventArgs e);
public event FileOpenHandler FileOpen;

step.3 :- Now do the operation suppose you have to send the file name on drag-drop or on a mouse click or on mouse hover any event then create the object of the class and set the file names and then pass like in this way :-
I have used on drag-drop so get the file names in this way :-
string[] files = (string[])drgevent.Data.GetData(DataFormats.FileDrop);
or you can do other way to get the file names.
Create the object and set the file names.
FileOpenEventArgs fileOpen = new FileOpenEventArgs();
fileOpen.FilePath = files;
OnFilesOpen(this, fileOpen);

Handles FileOpen event.
protected void OnFilesOpen(object sender, FileOpenEventArgs e)
{
if (FileOpen != null)
{
FileOpen(this, e);
}
}

Step.4 :- Now handle your event on the form where you can create the object of this form or you can handle the event here too but I handled the event on onother solution like :-
private solution.explorer lightView;
then again create delegate and event like:-
public delegate void FileOpenHandler(object sender, FileDataOpenEventArgs e);
public event FileOpenHandler FileOpen;
Now handles the event :-
lightView.FileOpen += new solution.explorer.FileOpenHandler(lightView_FileOpen);

void lightView_FileOpen(object sender, FileOpenEventArgs e)
{
string [] fileData = e.FilePath;
FileDataOpenEventArgs fileDataOpenEventArgs = new FileDataOpenEventArgs(fileData);
OnFilesOpen(fileDataOpenEventArgs);
}

Handle protected method :-
protected void OnFilesOpen(FileDataOpenEventArgs e)
{
if (FileOpen != null)
{
FileOpen(this, e);
}
}
now create the event where you have to open or do something for files :-
create the instance of above class where you handle your event.

private lightView_lightViewPanel = new lightView();
_lightViewPanel.FileOpen += new lightView.FileOpenHandler(_lightViewPanel_FileOpen);

private void _lightViewPanel_FileOpen(object sender, FileDataOpenEventArgs e)
{
if (e != null)
{
now play with your path accesss e.FilePath property of this event you will get path.
}
}

Happy to code.

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Generics in C#

Hi everyone..in .net 2.0 we do programming in a very smarter way Generics is the example like if we are using minimum finction to find minimum between two numbers they may be integer,string,object and may be some other data types.
Consider the following code :-
Returns minimum between two integers.
int Min( int a, int b )
{
if (a < b) return a;
else return b;
}

let suppose you have objects or string then this will not work.To use this code, we need a different version of Min for each type of parameter we want to compare then developers think to use in the folllowing manner :-
Returns minimum between two objects.
object Min( object a, object b )
{
if (a < b) return a;
else return b;
}

But less than operator (<) is not defined for the generic object type.So we need to use a coomon interface to use ex:-Icomparable. like in the following manner :-

IComparable Min( IComparable a, IComparable b )
{
if (a.CompareTo( b ) < 0) return a;
else return b;
}
By this way problem has been solved but now there is a big issue.A caller of Min that passes two integers should make a type conversion from IComparable to int and may be it gives an exception. like :-

int a = 7, b = 16
int c = (int) Min( a, b );
but .net 2.0 solved the issue using Generics.

This is the generic version of MIN method.
T Min( T a, T b ) where T : IComparable
{
if (a.CompareTo( b ) < 0) return a;
else return b;
}

Now you can call like in this manner :-
int a = 7 b = 16;
int c = Min( a, b );

Happy to code.

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Singleton Pattern

Singleton pattern is a design pattern that is used to restrict instantiation of a class to one object. This is very useful when only there is a need of single object which handles all the actions across the system.This pattern restrict the instantiation to a certain number of objects and this concept is to generalize the systems to operate more efficiently when only one object exists.
Example :-
The Abstract Factory, Builder, and Prototype patterns can use Singletons in their implementation

Implementation of Singleton pattern :-
///

/// Thread-safe singleton example without using locks
///

public sealed class SingletonClass
{
private static readonly SingletonClass singletonInstance = new SingletonClass();

// Explicit static constructor to tell C# compiler
// not to mark type as beforefieldinit
static SingletonClass()
{
}

private SingletonClass()
{
}

///

/// The public Instance property to use
///

public static SingletonClass SingletonInstance
{
get { return singletonInstance ; }
}
}
Happy to code...
Hiii...One more example to clear singleton approach :-
I have implement progress bar for ma current application so i am giving some reference here:-
#region Private Fields

private static StatusProgressBar _instance = null;

#endregion

#region Constructor

private StatusProgressBar()
{
this.Style = ProgressBarStyle.Blocks;
this.Step = 1;
}

#endregion

#region Properties

///

/// Get Singleton instance of progressBar
///

public static StatusProgressBar Instance
{
get
{
if (_instance == null)
{
_instance = new StatusProgressBar();
}

return _instance;
}
}

#endregion
Made the above class as public and access it suppose class name is StatusProgressBar

StatusProgressBar.Instance.PerformStep();
then if instance is already running then it will return that instance otherwise will return a new instance.

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Custom Number Formats.

I found something very interesting regarding number formats.have a look on the image

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What is LINQ?

■ LINQ is a uniform programming model for any kind of data. LINQ enables you to query
and manipulate data with a consistent model that is independent from data sources.
■ LINQ is just another tool for embedding SQL queries into code.
■ LINQ is yet another data abstraction layer.

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Remove special characters from string ?

public override string ToString()
{
string specialCharacters = "~!@#$%^&*<()+=`',.?>/\\\"";
string[] stringAfterRemovingSpecialCharacters= displayText.Split(specialCharacters .ToCharArray());
return string.Concat(stringAfterRemovingSpecialCharacters);
}

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File/Folder is being used by another process Error?

Hi Friends..
Resolved Error - File/Folder is being used by another process

As i discussed in my current project i made a self explorer.exe so i accessed all the folders,files .i am doing same behaviour as lioke window explorer.exe. But I was facing a error This file/folder is being used by another process and all that and i face all these errors when i rename,delete,move,copy,drag-drop.

Solution :- I add folders runtime and updation is all as real time.so I used shell com object and make tree using shell namespace like :-

node is treeNode of tree.

Shell32.FolderItem folderItem = (Shell32.FolderItem)node.Tag.FolderItem;
Shell32.Folder folder = (Shell32.Folder)folderItem.GetFolder;

then iterate thorugh foreach and used break statement because i add a dummynode in each node who have folders and when i expand that node then delete the dummynode and create the nodes for that treenode beacuase of efficiency.So on creating dummyNode i used foreach statement like :-

bool hasFolders = false;
foreach (Shell32.FolderItem item in folder.Items())
{
if (item.IsFileSystem && item.IsFolder && !item.IsBrowsable)
{
hasFolders = true;
break;
}
}
if (hasFolders)
{
TreeNode newTreeNode = new TreeNode();
newTreeNode.Tag = STRING_DUMMY_TREENODE;
treeNode.Nodes.Add(newTreeNode);
}
so this foreach actually its an iterator so when i use break statement so tis break from the loop but still it holds the object and shell thinks its used by some other program and all so dont use foreach if you using break statement like this :-

Shell32.FolderItems items = folder.Items();
for (int itemIndex = 0; itemIndex < items.Count; itemIndex++)
{
Shell32.FolderItem item = items.Item(itemIndex);
if (item.IsFileSystem && item.IsFolder && !item.IsBrowsable)
{
hasFolders = true;
break;
}
}
and now as above you will never face the error like file/folder is being used by another process so in your application if you are facing then firstly check it out and make sure you are not using any iterator.

Happy to code.

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List with ForEach

List Names = new List();
Names.Add("Saurabh");
Names.Add("Somu");
Names.Add("Sandy");

//For every item in the list, say you want to append the last name "Somu" and print it

//WITHOUT ForEach()
foreach (string name in Names)
{
Console.WriteLine(name + " Somu");
}

//WITH ForEach
Names.ForEach(delegate(string name) { Console.WriteLine( name + " Somu" ); });

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Yield Keyword

class Program
{
static void Main(string[] args)
{
List Names = new List();
Names.Add("saurabh");
Names.Add("somu");
Names.Add("vivek");

foreach (string item in GetNames(Names))
{
Console.WriteLine(item);
}
}

public static IEnumerable GetNames(List Names)
{
for (int i = 0; i < Names.Count; i++)
{
yield return Names[i];
}
}
}

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?? keyword

?? keyword is used to check null.

Example using if-else statement:-
if (tempString == null)
{
x = "Null string";
}
else
{
x = tempString ;
}
Console.WriteLine(x);

Example using ?? Keyword

string tempString = null;
string x = tempString ?? "Null string";
Console.WriteLine(x); //Prints "Null string"

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Problem about Instances...

Hii..Frends this is very genuine problem.
Functionality :-When i was developing Window Explorer control for my application then i just stuck in a problem I had three instances of window - explorer.. One is as similar as Window file explorer by which you can drag drop files and that will open in any editor.(We had given additional functionality like to show INF,INI,BAK and ORG files) and other two are as same as Window File - Folder Explorer like in left hand side Folder Explorer(TreeView) and Right hand side ListView which shows all the files with size,Modified date and type of file.and you can sort using coloumn click.(Like Window File detail view in windows) and the third one which is just below of this one has same feature but the root node of this tree will be a path where ever we want to show we said this is destination view and above one is source view .You can drag files from Source listView to Destination TreeView and ListView both and that will copy the whole directory at that path physically and You can add folder from source treeview to destination treeView and we can move folder and files from destination listView to destination treeview.We given the special functionality like we can add new folder,delete the folder and rename the folder.That all the features we have given in all the controls.

Problem:-I have only one control with three instances if i m doing some changes from application and rename and bla bla..n all the tree view has opened a same path then i want to make all the controls as real time like if we add a folder of some path then in all the controls will be the same...So i need some notification then i know the methods about shell if we add , delete and rename from shell then shell will send a notification to application and then WndProc method will send the notification to all the instances and to invoke shell methods i have already make a post related to How to Copy,Delete,Rename from Shell.

If you add delete , add folder,media and other devices and rename and all other changes then how system invokes the message and will reflect real time.

Enjoy the Code..

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How to Copy,Delete,Rename and Move files and create new directory using Shell32 in C#?

#region Enum
public enum FileOp
{
Move = 0x0001,
Copy = 0x0002,
Delete = 0x0003,
Rename = 0x0004
}

[Flags]
public enum FileOpFlags
{
MultiDestFiles = 0x0001,
ConfirmMouse = 0x0002,
Silent = 0x0004,
RenameCollision = 0x0008,
NoConfirmation = 0x0010,
WantMappingHandle = 0x0020,
AllowUndo = 0x0040,
FilesOnly = 0x0080,
SimpleProgress = 0x0100,
NoConfirmMkDir = 0x0200,
NoErrorUI = 0x0400,
NoCopySecurityAttributes = 0x0800,
NoRecursion = 0x1000,
NoConnectedElements = 0x2000,
WantNukeWarning = 0x4000,
NoRecursiveReparse = 0x8000
}

#endregion

#region Structure
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
public struct SHFILEOPSTRUCT
{
public IntPtr hwnd;
[MarshalAs(UnmanagedType.U4)]
public int wFunc;
public string pFrom;
public string pTo;
public short fFlags;
[MarshalAs(UnmanagedType.Bool)]
public bool fAnyOperationsAborted;
public IntPtr hNameMappings;
public string lpszProgressTitle;
}
#endregion

Import a shell method to copy file from one location to another,delete file,copy file and rename files and folders.
[DllImport("shell32.dll", CharSet = CharSet.Auto)]
public static extern int SHFileOperation(ref SHFILEOPSTRUCT FileOp);

Import a shell method to create a new directory.
[DllImport("shell32.dll")]
public static extern int SHCreateDirectoryEx(IntPtr hwnd, string pszPath, IntPtr psa);

To create a new folder :
private const string NULL_STRING = "\0";
newFolderPath is the path where you want to create your directory.
SHCreateDirectoryEx(this.Handle, newFolderPath + NULL_STRING, IntPtr.Zero);

To do all the file operation like move , copy ,delete and rename :-
public bool FileOperation(string sourceFileName, string destinationFileName, FileOp fileOp)
{
bool success = true;
try
{
SHFILEOPSTRUCT shf = new SHFILEOPSTRUCT();
shf.wFunc = (int)fileOp;
shf.fFlags = (short)FileOpFlags.AllowUndo | (short)FileOpFlags.NoConfirmation;
if(!string.IsNullOrEmpty(sourceFileName))
{
shf.pFrom = sourceFileName + NULL_STRING;
}
if(!string.IsNullOrEmpty(destinationFileName))
{
shf.pTo = destinationFileName + NULL_STRING;
}
int result = SHFileOperation(ref shf);

if (result != 0)
{
success = false;
}
}
catch (Exception exception)
{
MessageBox.Show(exception.Message, Application.ProductName, MessageBoxButtons.OK);
}
return success;
}

How to call this method :-
To Delete the file or folder.
FileOperation(newFolderPath, string.Empty, FileOp.Delete);

To Copy the File or Folder.
FileOperation(sourcePath, destinationPath, FileOp.Move);

To Rename the file or Folder.
FileOperation(sourcePath, destinationPath, FileOp.Rename);

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How to create FilePropertyDialog like Windows in C#?

#region Enum
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct SHELLEXECUTEINFO
{
public int cbSize;
public uint fMask;
public IntPtr hwnd;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpVerb;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpFile;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpParameters;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpDirectory;
public int nShow;
public IntPtr hInstApp;
public IntPtr lpIDList;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpClass;
public IntPtr hkeyClass;
public uint dwHotKey;
public IntPtr hIcon;
public IntPtr hProcess;
}
#endregion

private const int SW_SHOW = 5;
private const uint SEE_MASK_INVOKEIDLIST = 12;

[DllImport("shell32.dll")]
static extern bool ShellExecuteEx(ref SHELLEXECUTEINFO lpExecInfo);

Pass the file name for which you want to see the file property dialog.
public static void ShowFileProperties(string Filename)
{
SHELLEXECUTEINFO shellInfo = new SHELLEXECUTEINFO();
shellInfo .cbSize = System.Runtime.InteropServices.Marshal.SizeOf(info);
shellInfo .lpVerb = "properties";
shellInfo .lpFile = Filename;
shellInfo .nShow = SW_SHOW;
shellInfo .fMask = SEE_MASK_INVOKEIDLIST;
ShellExecuteEx(ref info);
}

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How to stop multiple instances running of my application using C# ?

public static void Main()
{
bool isNew = false;
Mutex mtx = new Mutex( true, "MyApp_Mutex", out isNew );
if( !isNew )
{
MessageBox.Show( "MyApp is already running." );
return;
}
}

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How many instances are running in my application using C# ?

#region Directives

using System.text;
using System.Threading;
using System.Reflection;

#endregion

public class TestApplication
{
#region Private Fields

The default instance
private static TestApplication DefValue = new TestApplication ();
The system-wide semaphore
private Semaphore semaphore;
Initial count for the semaphore(Randonm you can choose any big count)
private const int MAXCOUNT = 10000;
private static bool _pvInstance ;

#endregion

#region Properties

The PrevInstance property returns True if there was a previous instance running when the default instance was created
public static bool PrevInstance
{
get
{
return _pvInstance ;
}
}

Return the total number of instances of the same application that are currently running
public static int InstanceCount
{
get
{
// release the semaphore and grab the previous count
int prevCount = DefValue.semaphore.Release();
// acquire the semaphore again
DefValue.semaphore.WaitOne();
// evaluate number of other instances that are currently running.
return MAXCOUNT - prevCount;
}
}

#endregion

Constructor.
private TestApplication ()
{
// create a named (system-wide semaphore)
bool ownership = false;
// create the semaphore or get a reference to an existing semaphore

string appName = "TestApplication _" + Assembly.GetExecutingAssembly().Location.Replace(":", string.Empty).Replace("\\", string.Empty);
semaphore = new Semaphore( MAXCOUNT, MAXCOUNT, appName , out ownership);
// decrement its value
semaphore.WaitOne();
// if we got ownership, this app has no previous instances
_prevInstance = !ownership;
}
Destructor to destroy.
~TestApplication ()
{
// increment the semaphore when the application terminates
semaphore.Release();
}
}

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How to Create a Zip file using C#

public bool CreateZip(string ZipFileName)
{
try
{
Create an empty zip file

byte[] ZipFolder = new byte[]{100,75,50,16,10,5,8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
FileStream fs = File.Create(ZipFileName);
fs.Write(ZipFolder , 0, ZipFolder.Length);
fs.Flush();
fs.Close();
fs = null;
}
catch(Exception ignore)
{
}
return true;
}

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How to open a zip file using C# ?

#region Namespace
using Shell32;
#endregion

namespace TestApplicationToZip
{
class ZipApplication
{
public static void Main(string[] args)
{
Create the object of shell.
Shell sh = new Shell();
Create a namespace and folderItem for the existing folder path.
Folder ShellFolder = sh.NameSpace("D:\\saurabh.zip");
Folder DirectoryFolder = sh.NameSpace("D:\\Unzipped Files");
Traverse each file.
foreach (FolderItem folderItem in ShellFolder .Items())
{
DirectoryFolder .CopyHere(folderItem ,o);
}
}
}
}

Enjoy the code.

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Differences between Connected and disconnected architecture ?

Hii friends,Today one of my frend ask about what approach is better connected or disconnected architecture ..So let me explain more about this problem :-

As the nature of HTTP protocol,.Net web applications are always disconnected so your problem is about connected or disconnected data models.

"connected" data is always faster as compare to "disconnected" because of the internal optimizations provided by the data provider,data adopters and others like data tables but always remeber that fetch out the data when you need so disconnected data model is good.

Connected :-
**User can get the data from database in connection state using data reader,adaptor,data table.1 :- Using this communication will possible in between the front end & backend (UI and database).
2 :- This command object have some parameters and have some methods to execute stored procedure ExecuteNonQuery(),ExecuteReader(),ExecuteScalar(),
ExecuteXMLReader()
ExecuteNonQuery :- For executing DML statements.
ExecuteReader :- This method returns DataReader.
ExecuteScalar :- This method is used for executing those SQL statements which generates single value.
ExecuteXMLReader :- This method is mainly used for reading an XML file content.

Disconnected :-
** User can get the data from database in connectionless state using data set.

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What do you meant by Containment in C#?

Containment is the replacement of inheritence,no no if inheritance isn’t the right choice,then the answer is containment, also known as aggregation. Rather than saying that an object is an example of another object, an instance of that other object will be contained inside the object. So,instead of having a class look like a string, the class will contain a string (or array, or hash table).
The default design choice should be containment, and you should switch to inheritance only if needed(i.e., if there really is an “is-a” relationship).

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How to handle generic errors in WinApp using C# ?

Pass your exception or error through catch block to this method this will catch your error and show the messagebox regarding that error.

Method which take error exception as a parameter and handle that error.
public static void LogError(Exception ex)
{
string sourceName = "Application Name";
int errorCode = "99";
string message = "The application encountered an unknown error:";
msg += "\r\nExecuting Method: " + new System.Diagnostics.StackFrame(1, false).GetMethod().Name;
message += "\r\nError Message: " + ex.Message;

EventLog.WriteEntry(sourceName , msg, EventLogEntryType.Error, errorCode );
MessageBox.Show(msg, "ERROR", MessageBoxButtons.OKCancel, MessageBoxIcon.Error);
}

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What is interface and why we implement interfaces ?

Interface defined by using interface keyword .In visualstudio you can directly add class as a interface its not a class it behaves as a template of the class. Interfaces describe a group of related functionalities that can belong to any class or struct.Interfaces are provided in C# as a replacement of multiple inheritance because C# does not support multiple inheritance and it's very necessary to inherit the behaviour of one or more classes.classes can only implement the methods defined in the interface because in C#, an interface is a built-in keyword that declares a reference type that includes method declarations. if a base class implements an interface, the derived class inherits that implementation.

I am giving an example to better understand :-
Interface which contains profile name strings
public interface IProfile
{
string FirstName {get;}
string LastName {get;}
}
Implements IloggedUser interface.
public interface ILoggedUser
{
IProfile Profile
{
get;
set;
}
}
Class LoggedUser which implements ILoggedUser interface.
public class LoggedUser : ILoggedUser
{
protected IProfile _profile = null;
Constructor
public LoggedUser(IProfile Profile)
{
_profile=Profile;
}

public static LoggedUser Create(IProfile Profile)
{
LoggedUser User = new LoggedUser(Profile);
return User;
}
public IProfile Profile
{
get
{
if (_profile== null)
{
return _profile;
}
}
set
{
_profile=value;
}
}
}
Class profile which implements IProfile interface.
public class Profile : IProfile
{
string _firstName = string.Empty;
string _lastName = string.Empty;
public string FirstName
{
get
{
return _firstName;
}
}
public string LastName
{
get
{
return _lastName;
}
}
}

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How to combine two images into one image in C#?

using System.Drawing;

public static System.Drawing.Bitmap Combine(string[] files)
{
Create a list for images and read images
List images = new List();
Bitmap finalImage = null;

try
{
int width = 0;
int height = 0;

foreach (string image in files)
{
create a Bitmap from the file and add it to the list. Bitmap bitmap = new Bitmap(image);

Update the size of the final bitmap.
width += bitmap.Width;
if(bitmap.Height > height )
{
height = bitmap.Height ;
}
else
{
height = height ;
}
images.Add(bitmap);
}

create a bitmap to hold the combined image.
finalImage = new Bitmap(width, height);

Get a graphics object from the image so we can draw on it.
using (Graphics g = Graphics.FromImage(finalImage))
{
set background color.
g.Clear(Color.Black);

Go through each image and draw it on the final image.
int offset = 0;
foreach (Bitmap image in images)
{
g.DrawImage(image,
new System.Drawing.Rectangle(offset, 0, image.Width, image.Height));
offset += image.Width;
}
}

return finalImage;
}
catch(Exception ex)
{
if (finalImage != null)
{
finalImage.Dispose();
}

throw ex;
}
finally
{
//clean up memory
foreach (Bitmap image in images)
{
image.Dispose();
}
}
}

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Location of opening of dialog boxes(window form) in C#

In my application i used some dialog boxes like about of company some customize message boxes and all that in some dialog boxes I used start position as Center parent but i forget to pass the IWin32Window Owner in show dialog as a parameter regarding that when focus is lost from my application then dialog took desktop as a parent and opens in different locations so always pass window owner as a parameter.

About aboutInfo = new About();
aboutInfo .ShowDialog(this);
or,
aboutInfo .ShowDialog(this.toplevelcontrol);

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How to set image resolution and paint it in C# ?

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Imaging;

public class Form1 : System.Windows.Forms.Form
{
Constructor.
public Form1()
{
InitializeComponent();
}
Initialize all the controls.
private void InitializeComponent()
{
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(292, 273);
this.Text = "";
this.Resize += new System.EventHandler(this.Form1_Resize);
this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);

}
Main method(Entry point).
public static void Main()
{
Application.Run(new Form1());
}
Handles the paint event.Create the grapics for the image,then set the resolution and then draw the image.
private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
Graphics g = e.Graphics;
Bitmap bmp = new Bitmap("winter.jpg");

g.FillRectangle(Brushes.White, this.ClientRectangle);
bmp.SetResolution(600f, 600f);
g.DrawImage(bmp, 0, 0);
bmp.SetResolution(1200f, 1200f);
g.DrawImage(bmp, 180, 0);
}
Handles the resize event.
private void Form1_Resize(object sender, System.EventArgs e)
{
Invalidate();
}
}

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More Regular Expressions

To validate a URL with a regular expression :-
(http://|ftp://)([\w-\.)(\.)([a-zA-Z]+)

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C# Tutorial (Chapter - 1) Introduction about C# and .Net framework(1 :- .Net Plateform)

I :-.Net Plateform :-

The Microsoft® .NET platform provides all of the tools and technologies that
you need to build distributed Web applications. It exposes a languageindependent,
consistent programming model across all tiers of an application
while providing seamless interoperability with, and easy migration from,
existing technologies. The .NET platform fully supports the Internet’s platformneutral, standards-based technologies, including HTTP, Extensible Markup
Language (XML), and Simple Object Access Protocol (SOAP).

II :-The .NET Building Block Services :-

The .Net building block services are distributed programmable services that are availaible in both offline and online.A service can be invoked on stand alone computer not connected to the internet,provided by the server which is running inside from the company oer accessed by internet, This service can be used from the plateform which supports SOAP.Services include identity, notification and messaging,
personalization, schematized storage, calendar, directory, search, and software
delivery.

III :-The .NET Enterprise Servers :-
1: Microft Sql server - 2000
2: Microsoft Biztalk sever - 2000
3: Microsoft Host integration server - 2000
4: Microsoft Exchange 2000 Enterprise server
5: Microst Application center - 2000
6: Microsoft Internet security server - 2000

Microsoft Sql server - 2000 :- Supports XML functionality, support for Worldwide Web Consortium (W3C) standards, manipulate XML data by using Transact SQL (T-SQL), flexible Web-based analysis, and secure access to your data over the Web by using HTTP.

Microsoft Internet security server - 2000 :- Provides secure, fast, and manageable Internet connectivity. Internet Security and multilayer enterprise firewall and a scalable high-performance Web cache. It builds on Windows 2000 security.

Microst Application center - 2000 :- Provides a deployment and management tool for high-availability Web applications.

Microsoft Exchange 2000 Enterprise server :- Builds on the powerful Exchange messaging and collaboration technology by ntroducing new features, and further increasing the reliability,scalability, and performance of its core architecture.

Microsoft Biztalk sever - 2000 :- Provides enterprise application integration (EAI), business-to-business integration and to build dynamic business processes,the span applications and plate forms.

Microsoft Host integration server - 2000 Provides the best way to embrace Internet, intranet, and client/server technologies.

IV :-The .NET Framework Components :-
1:-Common Language Runtime
2:- Base Class Library
3:- ADO.NET: Data and XML
4:- Web Forms and Services
5:- User Interface

CLR(Comman Language Runtime) :- Central to the .NET framework is its run-time execution environment, known as the Common Language Runtime (CLR) or the .NET runtime. Code running under the control of the CLR is often termed
managed code.However, before it can be executed by the CLR, any sourcecode that we develop (in C# or some other language) needs to be compiled. Compilation occurs in two steps in .NET:
1. Compilation of source code to Microsoft Intermediate Language (MS-IL)
2. Compilation of IL to platform-specific code by the CLR

Components of CLR :-
1 :-Class loader : Manages metadata, as well as the loading and layout of classes.
ClassLoader classLoader = TestClass.getClassLoader();
URL url = cl.getResource("someFileName");
2 :-Garbage collector (GC) :-The garbage collector is .NET's answer to memory management,Having the application code responsible for de-allocating memory is the technique used by lower-level,high-performance languages such as C++. It is efficient, and it has the advantage that (in general)resources are never occupied for longer than unnecessary. The big disadvantage, however, is the frequency of bugs. Code that requests memory also should explicitly inform the system when it no longer requires that memory. However, it is easy to overlook this, resulting in memory leaks.Provides automatic lifetime management of all of your objects. This is a multiprocessor, scalable garbage collector.
3 :-Security engine :-It based on the origin of the code.
4 :-Debug engine :- Debug your program and trace the execution of code.
5:-Code manager :-Manages the code execution.
6 :-Exception manager :- It provides structured exception management,which is integrated with Windows Structured Exception Handling (SEH),provides all the system exception classes.
7 :-Thread support :-Supports multi threaded programming.
8 :-COM :-Provides Interoperability class and marshalling to and from COM.
9 :-Type checker :-This will not allow unsafe typecasting and uninitialized variables Il verifies guaranteed type safety.
10 :-Microsoft intermediate language :-Converts MSIL to native code.
11 :- Base Class Library :- Executes run time.

2:-Base Class library :- This library contains namespaces like header files in C,C++,It expose features at run time and provide some high services.
I am mentioning namespace and about their services :-

System.Collections :- You can see all the interfaces and classes included in this namespace from below link :-
http://msdn.microsoft.com/en-us/library/system.collections.generic.aspx

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C# Tutorials

Hello to all, My next thread is about C#,In my next thread i will divide the C# thread into chapters each chapter will contain all the details about C# and .Net framework its a step by step process so go through to all the thread and please post a comment or email me at saurabhjnumca@gmail.com about this thread please give critics about this thread.If you will study the coming thread then you will able to explain about .net and you can easily code in C# .

Regards,
Saurabh Singh

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How to create a session manager in .Net ?

To create a SessionManager to save User objects in memory. It would be HashMap of HaspMaps.
It can be used as:

SessionManager MySessionManager= New SessionManager()
Student S1 = New Student ("Saurabh");
Student S2 = New Student ("Sandeep");
Student S3 = New Student ("Deepak");

//To create session
MySessionManager.createSession(S1);
MySessionManager.createSession(S2);
//SAVING S1 MARKS
Marks phyMarks = New Marks ("Physcis", 90);
MySessionManager.Save(S1, "Physics", phyisicsMarks); //Physics is the key
Marks chemMarks New Marks("Chemistry",85);
MySessionManager.Save(S1, "Chemistry",chemistryMarks);
Marks mathsmarks = New Marks("Mathematics",100);
MySessionManager.Save(S1, "Mathematics" ,mathsMarks);

//SAVING S2 MARKS
Marks phyMarks = New Marks ("Physcis", 90);
MySessionManager.Save(S2, "Physics", phyMarks); //Physics is the key
Marks chemMarks New Marks("Chemistry",85)
MySessionManager.Save(S2, "Chemistry",chemMarks);
Marks mathsmarks = New Marks("Mathematics",100);
MySessionManager.Save(S2, "Mathematics" ,mathsMarks);

//SAVING S3 MARKS. NOTE: SESSION OF S3 IS NOT AVAILABLE. SO FIRST SESSION OF
S3 SHOULD BE CREATED AND THEN DATA SHOULD BE SAVED
Marks phyMarks = New Marks ("Physcis", 90);
MySessionManager.Save(S3, "Physics", phyMarks); //”Physics” is the key
Marks chemMarks New Marks("Chemistry",85);
MySessionManager.Save(S3, "Chemistry",chemMarks);
Marks mathsmarks = New Marks("Mathematics",100);
MySessionManager.Save(S3, "Mathematics" ,mathsMarks);

///How to retrieve data
Out.Print ("Phyiscis Marks of S1," & MySessionManager.get(S1, "Physics").marks);
Out.Print ("Phyiscis Marks of S3," & MySessionManager.get(S1, "chemistry").marks);

IN REAL WORLD SCENARIO, S1, S2, S3 SHOULD NOT BE PASSED TO
MYSESSIONMANAGER. THEY WOULD BE OBTAINED FROM CONTEXT.

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Tech-Giant(Jargons.. for Professionals): How to take Screenshot of panel,control and save it in a JPG format ?

Tech-Giant(Jargons.. for Professionals): How to take Screenshot of panel,control and save it in a JPG format ?

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How to take Screenshot of panel,control and save it in a JPG format ?

You can create a bitmap of screen and then save it give the stream or fileName and then dispose the object of screenshot.

Bitmap theScreenShot = new Bitmap(Screen.PrimaryScreen.Bounds.Width,
Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
theScreenShot.Save(stream_or_filename, ImageFormat.Jpeg);
theScreenShot.Dispose();

Another way to save the panel as a jpg format and you can take a print of your control using below method.
Use this event on your form :-
_document.PrintPage += new PrintPageEventHandler(document_PrintPage);

/// Prepare the page to be print for the area of the control to be printed.
private void document_PrintPage(object sender, PrintPageEventArgs e)
{
this.Dock = System.Windows.Forms.DockStyle.None;
this.Size = Temp_Image.Size;
//Takes away focus from any printed controls to make sure output is what we want.
this.Focus();
this.Refresh();
this.DrawToBitmap(Temp_Image, New System.Drawing.Rectangle(0, 0, Temp_Image.Width, Temp_Image.Height));
this.Dock = System.Windows.Forms.DockStyle.Fill;
e.Graphics.DrawImage(Temp_Image, e.MarginBounds);
e.Graphics.Clip = new Region(e.MarginBounds);
}
By this method you can print your control you just pass the object of your control (control will be panel,treeView,listView)and this will calculate the height ,width and then call the print method ,print preview or save as jpg file.

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Order of Event firing in ASP.Net

Event firing order becomes critically important when you add event handling code to master pages and the content forms based on them. The following events occur when ASP.NET renders a page. I’ve listed these events in the order in which they occur.

1 :-Content Page Pre Initializes
2 :-Master Page Child Controls Initialize
3 :-Content Page Child Controls Initialize
4 :-Master Page Initializes
5 :-Content Page Initializes
6 :-Content Page Initialize Complete
7 :-Content Page Pre Loads
8 :-Content Page Loads
9 :-Master Page Loads
10 :-Master Page Child Controls Load
11 :-Content Page Child Controls Load
12 :-Content Page Load Complete

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Lambda Expressions in C#

Lambda expressions makes the searching life much easier.Have a look on this example :-

public class TestLambdaProgram
{
public static void Main( string[] args )
{
List names = new List();

names.Add(“Saurabh”);
names.Add("Garima");
names.Add(“Vivek”);
names.Add(“Sandeep”);

string stringResult = names.Find( name => name.Equals(“Garima”));
}

You can print the whole list using this method :-

new List(names ).foreach(name => Console.WriteLine(name));

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Basics of .Net (What is IL,CLR,CTS,CLS ?)

1: IL(Intermediate Language) :-(IL)Intermediate Language is also known as MSIL (Microsoft Intermediate Language) or CIL (Common Intermediate Language). All .NET source code is compiled to IL. This IL is then converted to machine code at the point where the software is installed, or at run-time by a Just-In-Time (JIT) compiler. Microsoft Intermediate Language (MSIL) is a language used as the output of a number of compilers (C#, VB, .NET, and so forth). The ILDasm (Intermediate Language Disassembler) program that ships with the .NET Framework SDK (FrameworkSDK\Bin\ildasm.exe) allows the user to see MSIL code in human-readable format. By using this utility, we can open any .NET executable file (EXE or DLL) and see MSIL code.

MSIL commands are as follows:

ldstr string :—loads the string constant onto the stack.
call function(parameters) :—calls the static function. Parameters for the function should be loaded onto the stack before this call.
pop :—pops a value from the stack. Used when we don't need to store a value in the variable.
ret :—returns from a function.
I will discuss about MSIL in my next article.

2 :- CLR(Comman Language Runtime) Full form of CLR is Common Language Runtime and it forms the heart of the .NET framework.It is the implementation of CLI .The core runtime engine in the microsoft .net framework for executing assemblies. All Languages have runtime and its the responsibility of the runtime to take care of the code execution of the program. For example VC++ has MSCRT40.DLL,VB6 has MSVBVM60.DLL, Java has Java Virtual Machine etc. Similarly .NET has CLR. Internet Exlorer is the example of hosting CLR. CLR have following qualities :-

Garbage Collection :- CLR automatically manages memory thus eliminating memory leaks. When objects are not referred GC automatically releases those memories thus providing efficient memory management.

Code Access Security :- CAS grants rights to program depending on the security configuration of the machine. Example the program has rights to edit or create a new file but the security configuration of machine does not allow the program to delete a file. CAS will take care that the code runs under the environment of machines security configuration.

Code Verification :- This ensures proper code execution and type safety while the code runs. It prevents the source code to perform illegal operation such as accessing invalid memory locations etc.

IL( Intermediate language )-to-native translators and optimizer’s :- CLR uses JIT and compiles the IL code to machine code and then executes. CLR also determines depending on platform what is optimized way of running the IL
code.

3 :- CTS(Comman Type System) :- In order that two language communicate smoothly CLR has CTS (Common Type System).Example
in VB you have “Integer” and in C++ you have “long” in c u have "int" these datatypes are not compatible so the interfacing between them is very complicated. In order to able that two different languages can 1. Basic .NET Framework communicate Microsoft introduced Common Type System. So “Integer” datatype in VB6 and
“int” datatype in C++ will convert it to System.int32 which is datatype of CTS. CLS which is covered in the coming question is subset of CTS.

4 :-CLS(Common Language Specification) :- This is a subset of the CTS which all .NET languages are expected to support. It was always a
dream of Microsoft to unite all different languages in to one umbrella and CLS is one step towards that. Microsoft has defined CLS which are nothing but guidelines that language to follow so that it can communicate with other .NET languages in a seamless manner.

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What are different types of JIT ?

In .net there are three type of JIT.JIT compiler is a part of the runtime execution environment.
Three JIT are following :-

Pre-JIT :- Pre-JIT compiles complete source code into native code in a single compilation cycle. This is done at the time of deployment of the application.

Econo-JIT :- Econo-JIT compiles only those methods that are called at runtime. However, these compiled methods are removed when they are not required.

Normal-JIT :- Normal-JIT compiles only those methods that are called at runtime.
These methods are compiled the first time they are called, and then they are stored in cache. When the same methods are called again, the compiled code from cache is
used for execution.

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What is Manifest in .net ?

An assembly manifest contains all the metadata.It means Assembly metadata is stored in Manifest and it needed to specify the assembly's version requirements and security identity, and all metadata needed to define the scope of the assembly and resolve references to resources and classes.Some points are given please go through it :-
1:- The assembly manifest can be stored in either a Portable Executable file an .exe or dll file with Microsoft intermediate language (MSIL) code or in a standalone Portable Executable file that contains only assembly manifest information.

These four items
1 :- assembly name
2 :- version number
3 :- culture
4 :- strong name information
These four make up the assembly's identity.

Assembly name: A string which specifying the assembly's name.

Version number: A major and minor version number, and a revision and build number. The clr uses these numbers to enforce version policy. Versioning concept is only applicable to global assembly cache (GAC) as private assembly lie in
their individual folders.

Culture: Information on the culture or language the assembly supports. This information should be used only to designate an assembly as a satellite assembly containing culture- or language-specific information.

Satellite Assembly :- An assembly with culture information is automatically assumed to be a satellite assembly.

Strong name information: The public key from the publisher if the assembly has been given a strong name.

List of all files in the assembly: A hash of each file contained in the assembly and a file name. Note that all files that make up the assembly must be in the same directory as the file containing the assembly manifest.

Type reference information: Information used by the runtime to map a type reference to the file that contains its declaration and implementation. This is used for types that are exported from the assembly.

Information on referenced assemblies: A list of other assemblies that are statically referenced by the assembly. Each reference includes the dependent assembly's name, assembly metadata (version, culture, operating system, and so on), and public key, if the assembly is strong named.

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How to view a Assembly of your code (What is ILDASM ?)

When it comes to understanding of internals nothing can beat ILDASM. ILDASM basically converts the whole exe or dll in to IL code. To run ILDASM you have to go to "C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin". Note that i had v2.0 you have to probably change it depending on the type of framework version you have.

If you run IDASM.EXE from the path you will be popped with the IDASM exe program as
shown in figure ILDASM. Click on file and browse to the respective directory for the DLL whose assembly you want to view. After you select the DLL you will be popped with a tree view details of the DLL as shown in figure ILDASM. On double clicking on manifest you will be able to view details of assembly, internal IL code etc as shown in Figure Manifest View.

Note : The version number are in the manifest itself which is defined with the DLL or
EXE thus making deployment much easier as compared to COM where the information
was stored in registry. Note the version information in Figure Manifest view.
You can expand the tree for detail information regarding the DLL like methods etc

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How to copy the text from label in window form at run time ?

Designer view:
#region DesignerView
Create a context menu strip :
this.copyPathMenuItem = new System.Windows.Forms.ToolStripMenuItem();
this.labelContextMenuStrip.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
this.copyPathMenuItem});
this.labelContextMenuStrip.Name = "labelContextMenuStrip";
this.labelContextMenuStrip.Size = new System.Drawing.Size(100, 22);

this.copyPathMenuItem.Name = "copyPathMenuItem";
this.copyPathMenuItem.Size = new System.Drawing.Size(100, 22);

this.lblSelectedNodePath.ContextMenuStrip = this.labelContextMenuStrip;
private System.Windows.Forms.ToolStripMenuItem copyPathMenuItem;
#endregion

Now handles the label events like :-

private void lblSelectedNodePath_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right)
{
copyPathMenuItem.Visible = true;
copyPathMenuItem.Enabled = true;
}
}

Add an click event :-
copyPathMenuItem.Click += new EventHandler(copyPathMenuItem_Click);

Handles the click event :-

private void copyPathMenuItem_Click(object sender, EventArgs e)
{
string labelPath = lblSelectedNodePath.Text.Trim();
if (!string.IsNullOrEmpty(labelPath))
{
Clipboard.SetDataObject(labelPath, false);
}
}
Now you can paste your copy text anywhere Enjoy d Code .....

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How can I change the Border color of my control ?

public class MyButton : Button
{
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
int borderWidth = 1;
Color borderColor = Color.Blue;
ControlPaint.DrawBorder(e.Graphics, e.ClipRectangle, borderColor,
borderWidth, ButtonBorderStyle.Solid, borderColor, borderWidth,
ButtonBorderStyle.Solid, borderColor, borderWidth, ButtonBorderStyle.Solid,
borderColor, borderWidth, ButtonBorderStyle.Solid);
}
}

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How to change the color of Tab Control in c#

Steps :-
1. Set the TabControl's DrawMode to OwnerDraw.
2. Handle the DrawItem event.
private void ChangeColorOFTabControl(object sender, DrawItemEventArgs e)
{
Font TabFont;
Brush BackBrush = new SolidBrush(Color.Green); //Set background color
Brush ForeBrush = new SolidBrush(Color.Yellow);//Set foreground color
if (e.Index == this.tabControl1.SelectedIndex)
{
TabFont = new Font(e.Font, FontStyle.Italic | FontStyle.Bold);

}
else
{
TabFont = e.Font;
}
string TabName = this.tabControl1.TabPages[e.Index].Text;
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
e.Graphics.FillRectangle(BackBrush, e.Bounds);
Rectangle r = e.Bounds;
r = new Rectangle(r.X, r.Y + 3, r.Width, r.Height - 3);
e.Graphics.DrawString(TabName, TabFont, ForeBrush, r, sf);
//Dispose objects
sf.Dispose();
if (e.Index == this.tabControl1.SelectedIndex)
{
TabFont.Dispose();
BackBrush.Dispose();
}
else
{
BackBrush.Dispose();
ForeBrush.Dispose();
}
}

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How to set dropdown width according to longest string in C#

If you are using window control then use this method.
private void AdjustWidthComboBox_DropDown(object sender, System.EventArgs e)
{
ComboBox senderComboBox = (ComboBox)sender;
int width = senderComboBox.DropDownWidth;
Graphics g = senderComboBox.CreateGraphics();
Font font = senderComboBox.Font;
int vertScrollBarWidth =
(senderComboBox.Items.Count>senderComboBox.MaxDropDownItems)
?SystemInformation.VerticalScrollBarWidth:0;

int newWidth;
foreach (string s in ((ComboBox)sender).Items)
{
newWidth = (int) g.MeasureString(s, font).Width
+ vertScrollBarWidth;
if (width < newWidth )
{
width = newWidth;
}
}
senderComboBox.DropDownWidth = width;
}

If you are a web developer then :-
Get the length of longest string and pass it in unit.pixel method like this :-
DropDownList1.Width = Unit.Pixel(LengthOfTheLongestString)

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How to get the file size like windows file property control ?

//Create an object of FileInfo like :-
FileInfo fileObject = new FileInfo(selectedFilename);
Int64 fileSize = 0;
float sizeOfFile = 0
fileSize = fileObject.Length;
sizeOfFile = fileObject.Length;
private const int FILESIZE_IN_KB = 1024;
public const int FILESIZE_IN_MB = 1048576;
public const int FILESIZE_IN_GB = 1073741824;
public const long FILESIZE_IN_TB = 1099511627776;
private const int START_INDEX = 0;
private const string STRING_VALUE_ZERO = "0";
private const string STRING_VALUE_ONE = "1";
private const string SYMBOL_BYTES = "bytes";
private const string STRING_FORMAT = "n";
public const string FILESIZE_KB = "KB";
private const int FILE_SIZE_LIMIT = 100;
private const string STRING_FORMAT_UPTO_TWO_DECIMAL = ".00";
private const int FILE_SIZE_IN_BYTES = 102400;
private const int FILE_SIZE_IN_MegaBytes = 104857600;
private const long FILE_SIZE_IN_GIGABYTES = 107374182400;
private const string SYMBOL_SPACE = " ";

string size = FormatSize(fileSize,sizeOFFile);

private string FormatSize(Int64 fileSize, float sizeOFFile)
{
//Format number to KB
string stringSize = string.Empty;
NumberFormatInfo numberFormatInfo = new NumberFormatInfo();

Int64 fileSizeInKB = 0;
Int64 fileSizeInMB = 0;
long fileSizeInGB = 0;
float fileSizeInKBInFloat = 0;
float fileSizeInMBInFloat = 0;
float fileSizeInGBInFloat = 0;
string byteSize = string.Empty;

if (fileSize < FILESIZE_IN_KB)
{
if (fileSize == 0)
{
//zero byte
stringSize = STRING_VALUE_ZERO + SYMBOL_SPACE + SYMBOL_BYTES;
}
else
{
//less than 1K but not zero byte
stringSize = fileSize + SYMBOL_SPACE + SYMBOL_BYTES + SYMBOL_SPACE + SYMBOL_OPENING_BRACE + fileSize + SYMBOL_SPACE + SYMBOL_BYTES + SYMBOL_CLOSING_BRACE;
}
}
else if(fileSize < FILESIZE_IN_MB)
{
if (fileSize < FILE_SIZE_IN_BYTES)
{
fileSizeInKBInFloat = (sizeOFFile / (float)FILESIZE_IN_KB);
}
else
{
//convert to KB
fileSizeInKB = (fileSize / FILESIZE_IN_KB);
}
if (fileSizeInKBInFloat != 0)
{
stringSize = fileSizeInKBInFloat.ToString(STRING_FORMAT, numberFormatInfo);
}
else
{
//format number with default format
stringSize = fileSizeInKB.ToString(STRING_FORMAT, numberFormatInfo);
///If file Size is morethan 100 than replace decimal string to emptyString.
if (fileSizeInKB >= FILE_SIZE_LIMIT)
{
stringSize = stringSize.Replace(STRING_FORMAT_UPTO_TWO_DECIMAL, string.Empty);
}
}
///Sets the byteSize like 12345 into 12,345.
byteSize = fileSize.ToString(STRING_FORMAT, numberFormatInfo);
byteSize = byteSize.Replace(STRING_DECIMAL, string.Empty);
stringSize = stringSize + "KB" + SYMBOL_SPACE + SYMBOL_OPENING_BRACE + byteSize + SYMBOL_SPACE + SYMBOL_BYTES + SYMBOL_CLOSING_BRACE;
}
else if (fileSize < Constants.FILESIZE_IN_GB)
{
if (fileSize < FILE_SIZE_IN_MegaBytes)
{
fileSizeInMBInFloat = (sizeOFFile / (float)FILESIZE_IN_MB);
}
else
{
//convert to KB
fileSizeInMB = (fileSize / FILESIZE_IN_MB);
}
if (fileSizeInMBInFloat != 0)
{
stringSize = fileSizeInMBInFloat.ToString(STRING_FORMAT, numberFormatInfo);
}
else
{
//format number with default format
stringSize = fileSizeInMB.ToString(STRING_FORMAT, numberFormatInfo);

if (fileSizeInMB >= FILE_SIZE_LIMIT)
{
stringSize = stringSize.Replace(STRING_FORMAT_UPTO_TWO_DECIMAL, string.Empty);
}
}

///Sets the byteSize like 12345 into 12,345.
byteSize = fileSize.ToString(STRING_FORMAT, numberFormatInfo);
byteSize = byteSize.Replace(STRING_FORMAT_UPTO_TWO_DECIMAL, string.Empty);

stringSize = stringSize + "MB" + SYMBOL_SPACE + SYMBOL_OPENING_BRACE + byteSize +SYMBOL_SPACE + SYMBOL_BYTES + SYMBOL_CLOSING_BRACE;
}
else if(fileSize < FILESIZE_IN_TB)
{
if (fileSize < FILE_SIZE_IN_GIGABYTES)
{
fileSizeInGBInFloat = (sizeOFFile / (float)FILESIZE_IN_GB);
}
else
{
//convert to KB
fileSizeInGB = (fileSize / FILESIZE_IN_GB);
}
if (fileSizeInGBInFloat != 0)
{
stringSize = fileSizeInGBInFloat.ToString(STRING_FORMAT, numberFormatInfo);
}
else
{
//format number with default format
stringSize = fileSizeInGB.ToString(STRING_FORMAT, numberFormatInfo);

if (fileSizeInGB >= FILE_SIZE_LIMIT)
{
stringSize = stringSize.Replace(STRING_FORMAT_UPTO_TWO_DECIMAL, string.Empty);
}
}

///Sets the byteSize like 12345 into 12,345.
byteSize = fileSize.ToString(STRING_FORMAT, numberFormatInfo);
byteSize = byteSize.Replace(STRING_FORMAT_UPTO_TWO_DECIMAL, string.Empty);
stringSize = stringSize + "GB" + SYMBOL_SPACE + SYMBOL_OPENING_BRACE + byteSize + SYMBOL_SPACE + SYMBOL_BYTES + SYMBOL_CLOSING_BRACE;
}
return stringSize;
}

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Sort ListView on column click (like windows folder detail view in xp)

Step :1 Firstly Create the object of listviewcolumn sorter class.
private ListViewColumnSorter listviewColumnSorter=new ListViewColumnSorter();
Step :2 Set ListViewItemSorter property of listView
listView.ListViewItemSorter = listviewColumnSorter;
Handles columnclick event on your form like the above image.
I am pasting the images of listViewItemSorter class please go through it.This class sort the columns according to image,size,text,alphabet.

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Get AssociatedFileTypes (.txt = TextDocument)

///

/// Get File Type for given file.
///

/// Pass the path of file
///

This method returns Associated file type like :-
.pdf = Adobe Acrobat Document
.txt = Text Document

private string GetAssociatedFileType(string filePath)
{
private const string STRING_SPACE = " ";
string extension = string.Empty;
if (!string.IsNullOrEmpty(filePath))
{
string extension = Path.GetExtension(filePath);
}
RegistryKey key = Registry.ClassesRoot.OpenSubKey(extension);
while (key != null)
{
string name = (string)key.GetValue(null);
if (name == null)
{
return extension + STRING_SPACE + "File";
}
RegistryKey tempKey = Registry.ClassesRoot.OpenSubKey(name);
if (tempKey == null)
{
return name;
}
key = tempKey;
}
return extension + STRING_SPACE + "File";
}

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File System Watcher in C#(Get notified after any modification)

Drag FileSystemWatcher control in your form from toolbox and add the events for created,deletion and renaming.
Ex:-
#region Designer view

this.fileSystemWatcher.EnableRaisingEvents = true;
this.fileSystemWatcher.IncludeSubdirectories = true;
this.fileSystemWatcher.SynchronizingObject = this;
this.fileSystemWatcher.Created += new System.IO.FileSystemEventHandler(this.fileSystemWatcher_Created);
this.fileSystemWatcher.Deleted += new System.IO.FileSystemEventHandler(this.fileSystemWatcher_Deleted);
this.fileSystemWatcher.Renamed += new System.IO.RenamedEventHandler(this.fileSystemWatcher_Renamed);
public System.IO.FileSystemWatcher fileSystemWatcher;

#endregion
Create three bool variables to set true or false :-
#region Properties
private bool _fileDeleted = false;
private bool _fileRenamed = false;
private bool _fileCreated = false;

public bool FileDeleted
{
set
{
_fileDeleted = value;
}
get
{
return _fileDeleted;
}
}
public bool FileRenamed
{
set
{
_fileRenamed = value;
}
get
{
return _fileRenamed;
}
}
pblic bool FileCreated
{
set
{
_fileCreated = value;
}
get
{
return _fileCreated;
}
}
#endregion

#region EventHandlers

private void fileSystemWatcher_Renamed(object sender, RenamedEventArgs e)
{
_fileRenamed = true;
MessageBox.Show(e.Name + " Renamed in " + e.FullPath);
}
private void fileSystemWatcher_Deleted(object sender, FileSystemEventArgs e)
{
_fileDeleted = true;
MessageBox.Show(e.Name + " Deleted in " + e.FullPath);
}
private void fileSystemWatcher_Created(object sender, FileSystemEventArgs e)
{
_fileCreated = true;
MessageBox.Show(e.Name + " created in " + e.FullPath);
}

#endregion

By this property if you want to check file has been removed ,deleted from physical path then this will be true and you can check like if you have a tree view and you dont want to repopulate your tree view then use filesystemwatcher and repopulate the tree only when files have been changed,delete or rename. or you can throw a messagebox like above.

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