TreeView问题

请教各位，我手动邦定的TreeView的父和子节点，在TreeView里自动套用格式设置完不起任何作用。
ParentNodeStyle，HoverNodeStyle，SelectedNodeStyle属性设置完后无效，也就NodeStyle属性管用不知是怎么回事？

<asp:TreeView ID="MissionTree" runat="server" ImageSet="Simple" ShowLines=true Width="100%">
                    <ParentNodeStyle Font-Bold="False" />
                    <HoverNodeStyle Font-Underline="True" ForeColor="#5555DD" />
                    <SelectedNodeStyle Font-Underline="True" ForeColor="#5555DD"
                        HorizontalPadding="0px" VerticalPadding="0px" />
                    <NodeStyle Font-Names="Tahoma" Font-Size="10pt" ForeColor="Black"
                        HorizontalPadding="0px" NodeSpacing="0px" VerticalPadding="0px" />

            MissionTree.ShowLines = true;
            MissionTree.NodeWrap = true;
            TreeNode pNode = new TreeNode();
            TreeNode Node = new TreeNode();
            Node.Text = "A";
            Node.Value = "1";
            Node.Target = "Contentt";
            Node.SelectAction = TreeNodeSelectAction.None;
            Node.Expanded = true;
            MissionTree.Nodes.Add(Node);

            pNode.Text = "AA";
            pNode.Value = "2";
            pNode.Target = "Contentt";
            pNode.NavigateUrl = "asd.aspx";
            pNode.Expanded = true;
            Node.ChildNodes.Add(pNode);

            TreeNode pNode1 = new TreeNode();

            pNode1.Text = "机构";
            pNode1.Value = "AB";
            pNode1.Target = "Contentt";
            pNode1.NavigateUrl = "qwe.aspx";
            pNode1.Expanded = true;
            Node.ChildNodes.Add(pNode1);
--------------------编程问答-------------------- 在线等，顶上去！！！ --------------------编程问答-------------------- 继续等！！！！ --------------------编程问答-------------------- <NodeStyle Font-Names="Tahoma" Font-Size="10pt" ForeColor="Black"
                        HorizontalPadding="0px" NodeSpacing="0px" VerticalPadding="0px" />
也没有效果? --------------------编程问答-------------------- 不知道了

补充：.NET技术 ,  ASP.NET