Get HWND of a window i clicked on

Question

I'm making a program, with c++ and winapi, where you can click a button, then select a window and it changes the transparency of that window.

I have no problems of making the window transparent, but i can't get the hwnd of a window.

When I use this function the program just crashes (No errors are being printed to the console).

HWND getHWND(HWND self)
{
  HWND found = GetForegroundWindow();
  if(found == self || found == NULL)
    return getHWND(self);
  return found;
}

I tried using this, but I don't like it, because the user has only 2 seconds to click on another window. (I'know I could use a bigger delay, but then it might be to much.. so this isn't optimal)

HWND getHWND()
{
  Sleep(2000);
  return GetForegroundWindow();
}

Congratulations, you have a stack overflow. Just use a simple `while` loop rather than making your function recursive. — Jonathan Potter, May 29 '19 at 12:32
You're clicking on a window created by some other application and have your own process that is waiting for the foreground window to change? — jwezorek, May 29 '19 at 14:55

score 3 · Answer 1 · answered May 29 '19 at 18:35

3

Don't poll for the active window, especially not with a recursive function. Just let the OS notify you when a window is clicked.

When the user clicks on your button, you can use SetCapture(), or a mouse hook via SetWindowsHookEx(), to direct subsequent mouse clicks to your app even if they are clicking on someone else's window. When you detect a click, release the capture/hook, and then use WindowFromPoint() to get the HWND at the location of the click.

answered May 29 '19 at 18:35

Remy Lebeau

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I am using HWND handle and I am successfully getting the handle of a specific window but when I Try to display that window only black screen appears. Can you please tell me what could be the issue and how to solve that. – Abdul ahad Nov 11 '21 at 10:31

Get HWND of a window i clicked on

1 Answers1