C # Use winform to invalidate the red close button that comes with the form. Click Close to hide it.

Code

# Region Intercept Windows messages
Protected   Override   Void Wndproc ( Ref Message m)
{
Const   Int Wm_syscommand =   Zero X 0112 ;
Const   Int SC _close =   0xf060 ;
If (M. msg = Wm_syscommand && ( Int ) M. wparam = SC _close)
{
// Capture closed form messages
// User clicked close button
This . Hide ();
Return ;
}
Base . Wndproc ( Ref M );
}
# Endregion