TreeView

 <TreeView>

            <TreeViewItem Header="Desktop">

                <TreeViewItem Header="Computer">

                </TreeViewItem>

            </TreeViewItem>

            <TreeViewItem Header="Recycle Bin">

            </TreeViewItem>

            <TreeViewItem Header="Control Panel">

                <TreeViewItem Header="Programs" />

                <TreeViewItem Header="Security" />

                <TreeViewItem Header="User Accounts" />

            </TreeViewItem>

            <TreeViewItem Header="Network" >

            </TreeViewItem>

     </TreeView>

在 TreeView 中一定要显式地用 TreeViewItem 包装 Item!