Generall Drag/Drop interface

src/Gui/ViewProviderDocumentObject.h

@@ -89,6 +89,15 @@ public:
     virtual void finishRestoring();
     //@}
 
+    /** @name drag & drop handling */
+    //@{
+    /// get called if the user hover over a object in the tree 
+    virtual bool allowDrop(const std::vector<const App::DocumentObject*> &objList,Qt::KeyboardModifiers keys,Qt::MouseButtons mouseBts,const QPoint &pos);
+    /// get called if the user drops some objects
+    virtual void drop(const std::vector<const App::DocumentObject*> &objList,Qt::KeyboardModifiers keys,Qt::MouseButtons mouseBts,const QPoint &pos);
+    //@}
+
+
 protected:
     /*! Get the active mdi view of the document this view provider is part of.
       @note The returned mdi view doesn't need to be a 3d view but can be e.g.