在C ++上的两个MFC TreeList之间拖放

Question

I Need Drag&Drop item from one TreeList to another ThreeList, but find only tutorials to make this in same TreeList. Can anybony help with this? Also im interesting how drag and drop file or folder from file system (window explorer) to TreeList? Im using MFC C++. Thanks!

Answer 1

Without omitting the obligatory real answer to all MFC questions (which is "don't use MFC—unless it's 1997 where you live" ), OLE drag & drop will help you achieve both goals.

Though I don't have an MSVC handy at the moment, this example seems fairly thorough...with move, copy, and scrolling:

http://www.ucancode.net/CPP_Library_Control_Tool/OLE-DRAG-DROP-TREE-Control-CTreeCtrl-VC-Article.htm

You can use that as a basis. But then for dropping-in-from-Windows-Explorer, throw in an additional check in your OnDragEnter() and OnDragOver() methods to see if CF_HDROP data is available:

if (pDataObject->IsDataAvailable(CF_HDROP)) {
   /* Extract the DROPFILES data out of the pDataObject */
}

This article goes into the details of how to get a filename list out of that wacky DROPFILES OLE structure:

http://www.codeproject.com/Articles/840/How-to-Implement-Drag-and-Drop-Between-Your-Progra

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For contrast, if you want to see something that's NOT terribly designed, look at the Qt Drag & Drop samples:

http://doc.qt.nokia.com/4.7-snapshot/dnd.html#examples