[WPF]如何在DropDownButton的ListView中继续打开ContextMenu

Question

1. DropDownButton上有ListView
2. 当我在ListViewItem中单击鼠标右键时，我想显示ContextMenu

3. 但是我无法在下面的示例代码中显示ContextMenu

   <StackPanel>
       <toolkit:DropDownButton Content="Option">
           <toolkit:DropDownButton.DropDownContent >
               <StackPanel>
                   <ListView>
                       <ListView.ContextMenu>
                           <ContextMenu>
                               <MenuItem Header="Menuitem1"/>
                               <MenuItem Header="Menuitem2"/>
                           </ContextMenu>
                       </ListView.ContextMenu>
                       <ListViewItem Content="Listview1"/>
                       <ListViewItem Content="Listview2"/>
                   </ListView>
               </StackPanel>
           </toolkit:DropDownButton.DropDownContent>
       </toolkit:DropDownButton>
   </StackPanel>