Forces a redraw.
[Visual Basic .NET] Public Sub UpdateWindow ( _ )
[C#] public void UpdateWindow ( );
[C++] HRESULT UpdateWindow( void );
Use UpdateWindow to process pending Windows WM_PAINT messages immediately. This may be the case if you have a routine that takes a long time to execute and you need the window to refresh while the code executes. Typically, no drawing will occur until all your code has been executed and control returns to the ArcMap's message loop and the WM_PAINT message is handled. UpdateWindow forces the window to invalidate by sending a WM_PAINT message directly to the window; the normal ArcMap message queue is bypassed.
See UpdateWindow in MSDN for more information.