C++ Win32API WM_KEYDOWN and buttons

Question

I'm having a problem receiving message in WM_KEYDOWN. WM_KEYDOWN works just fine until I click any button in my app. From that point it no longer receives my input from the keyboard. How to fix it?

Answer 1

If you are using Win32 controls such as CreateWindowEx(NULL, L"BUTTON", ... this is expected Each control is actually a child window and is capturing all of the window messages after it has focus.

Once the button is clicked you can capture the WM_COMMAND - BM_CLICK message to then call SetFocus(hwnd) to refocus on your window (as Giswin mentioned).

Answer 2

Probably your window has no focus before you click any button on your app. you can add code somewhere in your app to set focus programmatically:

yourwindow->SetFocus(); 

or use winapi:

::SetFocus(hWnd);

Answer 3

Just in case anyone is wondering, I (unsurprisingly) noticed the same behavior for handling WM_CHAR responses in my WindowProcedure callback as well. As soon as you click a button, the focus changes from the main window to the button control (which is a child window) and keyboard presses no longer have any effect.

As suggested by @NTSCCobalt, adding a simple SetFocus( main window handler ) in your WM_COMMAND cases will solve the problem, eg

case DEL__BUTTON:{
     <Button specific code>
     SetFocus(hwnd);
     return 0;
   }