TreeView项目拉伸

Question

我有代码：

 <TreeView Name="fileList" HorizontalContentAlignment="Stretch">   
     <TreeViewItem >
         <Grid Background="Aquamarine" HorizontalAlignment="Stretch">
             <TextBlock Text="some text"/>
         </Grid>
     </TreeViewItem>
 </TreeView>

带有Grid的{​​{1}}不会伸展。我该如何伸展呢？ https://leecampbell.com/2009/01/14/horizontal-stretch-on-treeviewitems/解决方案不起作用