To close the application from task manager.

If you have closed your appplication but still it runs in task manager then you can use this method to kill the thread.It happens only when some thread of your application is not closed.

Code:-

public const int SC_CLOSE = 0xF060;
public const int WM_SYSCOMMAND = 0x0112;

//Override method when You will close the window
protected override void WndProc(ref System.Windows.Forms.Message m)
{
if (m.Msg == WM_SYSCOMMAND && (int)m.WParam == SC_CLOSE)

//close the application
MyClose();
// your method that cleans everything up and then runs
// System.Environment.Exit(0) which WILL close the threads forcefully if needed

base.WndProc(ref m);
}