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

Question

I am creating window inside my program, then sending HWND of this window to another application. Will drawing on window's HDC be valid for another process?

See [Thread affinity of user interface objects, part 1: Window handles](https://devblogs.microsoft.com/oldnewthing/20051010-09/?p=33843) and [Thread affinity of user interface objects, part 2: Device contexts](https://devblogs.microsoft.com/oldnewthing/20051011-10/?p=33823). — IInspectable, Feb 10 '23 at 09:26

Gabe · Accepted Answer · 2011-04-06T01:36:59.007

5

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.

edited Apr 06 '11 at 01:36

answered Apr 05 '11 at 22:36

Gabe

84,912
12
139
238

score 2 · Answer 2 · answered Apr 05 '11 at 22:36

2

Unfortunately you can do this.

answered Apr 05 '11 at 22:36

Richard Schneider

34,944
9
57
73

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

2 Answers2

Linked