Win11 - User32.GetRawInputData fails to read data since 24H2

Vít H 0

Background:

We are using HwndHost class to host child window inside WPF application. From WndProc method we are forwarding input messages (WM_INPUT) to child process/window using User32.SendMessage. The child process/window WndProc method then receives the message and reads from it using User32.GetRawInputData.

I can confirm it works fine in Win10 and Win11 23H2.

Since 24H2 the GetRawInputData method from user32.dll is not able to read data(lParam) from forwarded WM_INPUT message from parent window/process.

returned result is -1 and lastWin32Error is set to 6 - invalid handle.

Short repro sample app

David Lowndes 2,590 Reputation points MVP

2025-01-28T16:59:29.51+00:00

A simple (as possible) repro project would be needed so that you can report the issue to MS.
Viorel 119.6K Reputation points

2025-01-28T17:00:11.13+00:00

It seems that the implementation should be fixed. It must not rely on features discovered through experiments. The raw data probably can be got in WndProc and then sent to child process. Or maybe the child process can be converted to a DLL or Class Library.
Vít H 0 Reputation points

2025-01-28T17:36:53.29+00:00

edit: link to dropbox with repro
David Lowndes 2,590 Reputation points MVP

2025-01-28T18:19:03.47+00:00

OK, I can reproduce what you say: All OK with Win10 & 11 (23H2 at least), problem occurs on Win 11 24H2 (I tried Win11 24H2 on ARM). Unless someone here can see any issue with your code (I can't), you'll probably need to report this to MS using paid support - though you shouldn't have to pay if it's a bug.
Viorel 119.6K Reputation points

2025-01-28T18:59:53.6866667+00:00

If RegisterRawInputDevices is called inside the child process (which is therefore entitled to perform GetRawInputData) and is removed from main process, then your sample seems to work better.

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Win11 - User32.GetRawInputData fails to read data since 24H2

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