xml格式的文本付值给 menu 控件，Selectable 属性 不能别被设置

以下代码可以正常运行，但在 
                                                      <asp:MenuItemBinding   NavigateUrlField="Href"   DataMember="Item"       TextField="Label"   Selectable=   “YnSelectdd”> </asp:MenuItemBinding>         添加了   Selectable=   “YnSelectdd”就抱错 
以下是页面和cs代码 
页面代码 
      <form   id="form1"   runat="server"> 
                <div> 
                        <fieldset   style="width:   240px"> 
                                <legend   class="mainTitle"> 实现Menu控件绑定XML文件 </legend> 
                                <asp:Menu   ID="Menu1"   runat="server"   DataSourceID="XmlDataSource1"   Orientation="Horizontal" 
                                        StaticSubMenuIndent="0px"> 
                                        <DataBindings> 
                                                <asp:MenuItemBinding   NavigateUrlField="Href"   DataMember="Item"       TextField="Label"> </asp:MenuItemBinding> 
                                                <asp:MenuItemBinding   NavigateUrlField="Href"   DataMember="Option"       TextField="Label"> </asp:MenuItemBinding> 
                                    
                                        </DataBindings> 
                                </asp:Menu> 
                                <asp:XmlDataSource   ID="XmlDataSource1"   runat="server"     > </asp:XmlDataSource> 
                                    
                                <br   /> 
                                <br   /> 
                        </fieldset> 
                        </div> 
        </form> 
cs代码 
  protected   void   Page_Load(object   sender,   EventArgs   e) 
        { 
            string   abc   =   " <?xml   version=\"1.0\"   encoding=\"utf-8\"   ?> "   + 
                                        " <System> "   + 
                                                " <Item   Label=\"我的文档\"   Href=\"PageA.aspx\"   YnSelectdd=\"false\"   > "   + 
                                                        " <Option   Label=\"文件存储\"     Href=\"PageA1.aspx\"   YnSelectdd=\"true\"   /> "   + 
                                                        " <Option   Label=\"电子邮件\"     Href=\"PageA2.aspx\"   YnSelectdd=\"true\"   /> "   + 
                                        " </Item> "   + 
                                                " <Item   Label=\"系统配置\"   Href=\"PageB.aspx\"   YnSelectdd=\"false\"   > "   + 
                                                        " <Option   Label=\"外观调整\"     Href=\"PageB1.aspx\"   YnSelectdd=\"true\"   /> "   + 
                                                        " <Option   Label=\"设置参数\"     Href=\"PageB2.aspx\"   YnSelectdd=\"true\"   /> "   + 
                                        " </Item> "   + 
                                        " </System> ";                 XmlDataSource1.Data   =   abc; 
        }