<div style="float:left">
        <asp:TreeView ID="TreeView1"  runat="server" OnSelectedNodeChanged="TreeView1_SelectedNodeChanged" Width="221px">
            <Nodes>
                <asp:TreeNode Text="根1" Value="1">
                    <asp:TreeNode Text="1.1" Value="1.1"></asp:TreeNode>
                    <asp:TreeNode Text="1.2" Value="1.2"></asp:TreeNode>
                </asp:TreeNode>
                <asp:TreeNode Text="根2" Value="2">
                    <asp:TreeNode Text="2.1" Value="2.1"></asp:TreeNode>
                    <asp:TreeNode Text="2.2" Value="2.2"></asp:TreeNode>
                </asp:TreeNode>
                <asp:TreeNode Text="XXX成本管理" Value="3">
                    <asp:TreeNode Text="小易" Value="3.1"></asp:TreeNode>
                    <asp:TreeNode Text="www" Value="3.2"></asp:TreeNode>
                    <asp:TreeNode Text="rrrr" Value="rrrr"></asp:TreeNode>
                    <asp:TreeNode Text="yyyy" Value="yyyy"></asp:TreeNode>
                </asp:TreeNode>
            </Nodes>
        </asp:TreeView>
    </div>
        <asp:ListBox ID="ListBox1" runat="server" Height="225px" Width="265px" SelectionMode="Single"></asp:ListBox>
        <asp:Button ID="btn02" runat="server" OnClick="btn02_Click" Text="删除"/>

 protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
    {
        InsertListBox();
    }

    private void InsertListBox()
    {
        if (this.TreeView1.SelectedNode.Parent.Value=="3")
        {
            if (this.ListBox1.Items.FindByValue(this.TreeView1.SelectedNode.Value) == null)
            {
                ListItem list = new ListItem(this.TreeView1.SelectedNode.Text, this.TreeView1.SelectedNode.Value);
                this.ListBox1.Items.Add(list);
            }

        }
    }
    protected void btn02_Click(object sender, EventArgs e)
    {
        this.ListBox1.Items.Remove(this.ListBox1.SelectedItem);
    }