Question

我从我网站上的网页收到Object reference not set to an instance of an object错误通过电子邮件发送给我。当我去那个页面时，我没有遇到任何错误。有人可以根据这个堆栈跟踪解释“可能”发生的事情。我知道渲染有问题，但我不知道从哪里开始......谢谢。

at ASP.controls_si_item_ascx.__Render__control1(HtmlTextWriter __w, Control parameterContainer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Control.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Control.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Control.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Control.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Page.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Answer 1

在我的Web.config文件中设置Debug =“True”后，我能够看到问题的原因。

终于找到了答案:)在我的.ascx文件中，我有一些JavaScript根据控件ID选择了一个选项卡。事实证明，在某些情况下控制不可用，因此会引发对象引用错误。这是我的代码：

var hdnSCSSelectedTabIndex=$('#<%= hdnSCSSelectedTabIndex.ClientID %>');
var tabIndex = hdnSCSSelectedTabIndex.val();

我现在正在这样做：

<% if (hdnSCSSelectedTabIndex != null) { %>
    var hdnSCSSelectedTabIndex=$('#<%= hdnSCSSelectedTabIndex.ClientID %>');
    var tabIndex = hdnSCSSelectedTabIndex.val();
<% } %>

已排除问题。

希望这有助于其他人：）

Answer 2

如果代码隐藏中发生异常，您可以尝试使用调试版本来获取堆栈跟踪中的行号。
另外，我会查看IIS请求日志以获得导致此请求的线索。

查看web.config的compilation部分。您可以在那里启用调试模式，它应该将行号添加到我认为的堆栈跟踪中。

有人能帮我理解这个堆栈跟踪吗？

2 个答案: