Re: Drag files onto my app

"AliR \(VC++ MVP\)" <AliR@online.nospam>
Tue, 26 Aug 2008 10:00:55 -0500
The only way I could do this is to handle the drag and drop myself.

What you will need to do is to first get rid of the call to DragAcceptFiles.

Then use multi-inheritance to derive your CMainFrame class from both
CMDIFrameWnd and COleDropTarget (don't worry about this, it is perfectly
Then in your OnCreate method call Register(this); to register the frame
window as a drop target. Then catch the WM_CLOSE message to revoke the drop
target from the window by calling Revoke();

Next is handling the drag and drop.
You will need to override a few methods that are in COleDropTarget, mainly :
OnDragEnter, OnDragOver, OnDrop, and return the appropriate drop operation
based on the file type being passed in.

Let me know if you need an example app to get you rolling.

"GT" <> wrote in message

What method / event do I need in my CWinApp class to control the mouse
cursor image (show a 'no entry' for certain file types) when the user
drags a file onto my app. I have enabled dragAcceptFiles, but the user can
currently drag any file onto our app. I correctly handle things in my
OnFileOpen, but I want to limit the drag to certain file extensions to
prevent a problem (that we have with image files).


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