CView::OnDropEx

virtual DROPEFFECT OnDropEx( COleDataObject* pDataObject, DROPEFFECT dropDefault, DROPEFFECT dropList, CPoint point );

Return Value

The drop effect that resulted from the drop attempt at the location specified by point. This must be one of the values indicated by dropEffectList. Drop effects are discussed in the Remarks section.

Parameters

pDataObject

Points to the COleDataObject that is dropped into the drop target.

dropDefault

The effect that the user chose for the default drop operation based on the current key state. It may be DROPEFFECT_NONE. Drop effects are discussed in the Remarks section.

dropList

A list of the drop effects that the drop source supports. Drop effect values can be combined using the bitwise OR (|) operation. Drop effects are discussed in the Remarks section.

point

The current mouse position relative to the view client area.

Remarks

Called by the framework when the user releases a data object over a valid drop target. The default implementation is to do nothing and return a dummy value ( -1 ) to indicate that the framework should call the OnDrop handler.

Override this function to implement the effect of an right mouse-button drag and drop. Right mouse-button drag and drop typically displays a menu of choices when the right mouse-button is released.

Your override of OnDropEx should query for the right mouse-button. You can call GetKeyState or store the right mouse-button state from your OnDragEnter handler.

• If the right mouse-button is down, your override should display a popup menu which offers the drop effects support by the drop source.
  • Examine dropList to determine the drop effects supported by the drop source. Enable only these actions on the popup menu.
    
    
  • Use SetMenuDefaultItem to set the default action based on dropDefault.
    
    
  • Finally, take the action indicated by the user selection from the popup menu.
• If the right mouse-button is not down, your override should process this as a standard drop request. Use the drop effect specified in dropDefault. Alternately, your override can return the dummy value ( -1 ) to indicate that OnDrop will handle this drop operation.

Use pDataObject to examine the COleDataObject for Clipboard data format and data dropped at the specified point.

Drop effects describe the action associated with a drop operation. See the following list of drop effects:

• DROPEFFECT_NONE   A drop would not be allowed.
  
  
• DROPEFFECT_COPY   A copy operation would be performed.
  
  
• DROPEFFECT_MOVE   A move operation would be performed.
  
  
• DROPEFFECT_LINK   A link from the dropped data to the original data would be established.
  
  
• DROPEFFECT_SCROLL   Indicates that a drag scroll operation is about to occur or is occurring in the target.

For more information on setting the default menu command, see SetMenuDefaultItem in the Win32 documentation and CMenu::GetSafeHmenu in this volume.

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See Also   CView::OnDragEnter, CView::OnDragOver, CView::OnDrop, CView::OnDragLeave, COleDropTarget::OnDropEx