Getting the containing window of a known control using the control's handle

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Getting the containing window of a known control using the control's handle

This is probably an easy one for a GUI programmer, which I'm not...

In a tool I'm working on (GUI "spy" for internal use) I have the handle of a control the user has chosen. I would like to get the handle of the window that contains the control, in order to sent it a certain message. Now:

The control could be of various types, and possibly the window itself
The control is created by another process
The containing window can be an MDI child, main, pop-up, whatever
I'd rather not use MFC

So, what's the easiest way to get it done?

+1 A:

Use the Win32 API call ::GetParent(HWND childWindowHandle);

Documentaiton here

Jason Williams 2009-06-14 13:52:47

I tried that, but couldn't figure out when to stop when climbing up the parents/owners chain. The control might be on top of others, which means I'm not always looking for the direct parent, but rather for one of the ancestors.

eran 2009-06-14 14:02:30

Stop when you find a window with WS_CAPTION in its style?

RichieHindle 2009-06-14 14:16:09

That's not bad, but not perfect. The target app does have at least one window without a title bar (floating drag and drop target), which cannot be recognized this way. But it covers most cases, and if no other solution is found I can make do with that.

eran 2009-06-14 14:27:33

+1 A:

Use GetAncestor() with the GA_PARENT flag. This will retrieve a parent window but not an owner window. (You can call it repeatedly to handle the case of nested controls.)

Peter Ruderman 2009-06-14 14:35:47

Which leads back to the question how do I know I've reached the actual window, and should stop calling GetAncestor? Checking for WS_CAPTION was suggested by RichieHindle, any other idea?

eran 2009-06-14 14:43:38

By actual, do you mean the top-level window? The top level window is the one you get with the last call to GetAncestor(). Calling GetAncestor(hwnd, GA_PARENT) will return NULL if hwnd is a top-level window.

Peter Ruderman 2009-06-14 14:45:32

When I used GetAncestor on a control that resided on an MDI client window, I looped all the way up to the application window (the MDI frame). Not sure if the MDI is the problem, but bottom line is that I did not get the NULL on the window I was hoping to.

eran 2009-06-14 15:15:53

That's a little surprising. I guess you'll have to write a special case for this. Use GetWindowLong() with GWL_EXSTYLE to check for the WS_EX_MDICHILD style.

Peter Ruderman 2009-06-14 15:42:42

ansaurus

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Getting the containing window of a known control using the control's handle

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