htmlanchor.rendercontrol抛出无效异常

Question

我有这个代码

   var anchor = new HtmlAnchor {HRef = temp, InnerText = this.LinkDescription};
            anchor.Attributes.Add("class", "navActive back");
            anchor.ServerClick += new EventHandler(AnchorServerClick);
            writer.Write("<div id="leftnav"><ul><li>");
            anchor.RenderControl(writer);
            writer.Write("</li></ul></div>");

在自定义网络控件中。我在Anchor.rendercontrol中得到了无效的例外，为什么？我调试了上述，作家也不是无效的，也不是锚。那里发生了什么？谢谢！

编辑：我正在添加用于调试目的的堆栈跟踪

[NullReferenceException: Object reference not set to an instance of an object.]
System.Web.UI.HtmlControls.HtmlAnchor.GetPostBackOptions() +107
System.Web.UI.HtmlControls.HtmlAnchor.RenderAttributes(HtmlTextWriter writer) [phone]
System.Web.UI.HtmlControls.HtmlControl.RenderBeginTag(HtmlTextWriter writer) +56
System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +26
CER.Portal.Dashboard.Controls.BackLink.Render(HtmlTextWriter writer) +1151

Answer 1

查看getPostbackoptions方法的代码，您要么需要将页面属性设置为当前页面，要么将casusesvalidation属性设置为false：

private PostBackOptions GetPostBackOptions()
{
   PostBackOptions options = new PostBackOptions(this, string.Empty) 
   {
      RequiresJavaScriptProtocol = true
   };
   if (this.CausesValidation && (this.Page.GetValidators(this.ValidationGroup).Count > 0))
   {
      options.PerformValidation = true;
      options.ValidationGroup = this.ValidationGroup;
   }
   return options;
}

添加 anchor.page = this.page 或 anchor.causesvalidation = false 在rendercontrol调用之前。