is it possible to draw on HWND created by another process?

I am creating window inside my program, then sending HWND of this window to another application. Will drawing on window's HDC be valid f开发者_Python百科or another process?

Windows are owned by other windows, not by processes. You can draw to any HWND on your desktop (at least if the window has the same integrity -- I'm not sure what happens if they don't).

Web browsers that host plug-ins or tabs in a separate process generally make use of this functionality.

Unfortunately you can do this.