Thank you for your answer.

So "what is this all about":

I have an application with lots of different widgets (treeviews, listviews, iconviews .... ). All widgest support dnd (all of them are still old qt3 style, but will/should () be "converted" soon). In my (derived) QTreeView I want do accept the drags from some of the other widgets, but not from all of the other widget. I thought the dragEnterEvent can (has to) be used for defining which events are accepted and which are not:

Qt Code: 
  1. void myQTListView::dragEnterEvent(QDragEnterEvent *e)
  2. {
  3. 	if ( e )
  4. 	{
  5. 		if ( e->provides("mystuff/mything") )
  6. 		{
  7. 			e->accept();
  8. 		}
  9. 		else
  10. 		{
  11. 			e->ignore();
  12. 		}
  13. 	}
  14. }
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I also have different items (all derived from QTreeWidgetItem of course) in my treeview. Some of them accept drops and some of them don't. So I use the dragMoveEvent to get the "current dropping target" by calling

Qt Code: 
  1. void myQTListView::dragMoveEvent(QDragMoveEvent *e)
  2. {
  3. 	QTreeWidgetItem *item = itemAt(e->pos());
  4.  
  5. 	bool accept = false;
  6.  
  7. 	if ( item )
  8. 	{
  9. 		if ( dynamic_cast<MySpecialListViewItem*>(item) )
  10. 		{
  11. 			accept = true;
  12. 		}
  13. 	}
  14.  
  15. 	if ( accept )
  16. 	{
  17. 		e->accept();		
  18. 	}
  19.         else
  20.         {
  21.                  e->ignore();
  22.         }
  23. }
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and check (by dynamic cast) if this (derived) QTreeWidgetItem is one of the items that accept drops.

I use the event->accept() or event->ignore() function to indicate if dropping is possible or not.

ps. Sorry that this has become a beginner tutorial on using drag and drop with QTreeViews, maybe I was running completely in the wrong direction?