The TreeView_CreateDragImage macro creates a dragging bitmap for the specified item in a tree-view control, creates an image list for the bitmap, and adds the bitmap to the image list. An application can display the image when dragging the item by using the image list functions. You can use this macro or explicitly send the TVM_CREATEDRAGIMAGE message.
Returns the handle of the image list to which the dragging bitmap was added if successful or NULL otherwise.
If you create a tree-view control without an associated image list, you cannot use the TreeView_CreateDragImage macro to create the image to display during a drag operation. You must implement your own way to support drag and drop cursor.