删除treeview子节点的奇怪有关问题

删除treeview子节点的奇怪问题？
TreeView.Nodes.Remove(TreeView.SelectedNode);   为什么只能删除根节点，而不能删除其下的子节点，web端控件，哪里有问题啊？谢谢


[解决办法]
我在vb中是这么用的
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim parentNode As TreeNode = TreeView1.SelectedNode.Parent
parentNode.Nodes.Remove(TreeView1.SelectedNode)
End Sub
[解决办法]
//写了一段代码,参考一下.
TreeView tv = new TreeView();//root
TreeNode tn = new TreeNode();//first
TreeNode tn1 = new TreeNode();//second

tn.Name = "aa ";
tn.Text = "aa.text ";
tv.Nodes .Add(tn);

tn1.Name = "aa1 ";
tn1.Text = "aa1.text ";
tn.Nodes.Add(tn1);

MessageBox.Show(tv.Nodes[ "aa "].Text);
MessageBox.Show(tv.Nodes[ "aa "].Nodes[ "aa1 "].Text);