How do I find why I get "Exception of type 'System.Web.HttpUnhandledException' was thrown"?

Question

I'm getting

System.Web.HttpException
Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerWrapper'.
Stack is
at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride)
at System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage)
at System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm)
at System.Web.Mvc.ViewPage.RenderView(ViewContext viewContext)
at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)
at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)

and inner exception is

System.Web.HttpUnhandledException
Exception of type 'System.Web.HttpUnhandledException' was thrown.
Stack is
at System.Web.UI.Page.HandleError(Exception e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at System.Web.Mvc.ViewPage.ProcessRequest(HttpContext context)
at System.Web.Mvc.ViewUserControl.ViewUserControlContainerPage.ProcessRequest(HttpContext context)
at System.Web.Mvc.ViewPage.RenderView(ViewContext viewContext)
at System.Web.Mvc.ViewUserControl.RenderView(ViewContext viewContext)
at System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(HtmlHelper htmlHelper, String partialViewName)
at ASP.views_mycontroller_myaction_aspx.__RendermyactionContent(HtmlTextWriter __w, Control parameterContainer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at ASP.views_shared_my_master.__Render__control1(HtmlTextWriter __w, Control parameterContainer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.Mvc.ViewPage.Render(HtmlTextWriter writer)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at System.Web.Mvc.ViewPage.ProcessRequest(HttpContext context)
at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.<>c__DisplayClass4.<Wrap>b__3()
at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.Wrap[TResult](Func`1 func)
at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride)

I've seen similar stuff in many other questions and usually there's some more or less clear message from which the problem cause can be deduced.

In my case there's just Exception of type 'System.Web.HttpUnhandledException' was thrown.

How do I extract additional information from that HttpUnhandledException to try find why it was thrown?

Answer 1

Turns out my code was not extracting the InnerException of that HttpUnhandledException. I've grabbed IIS sources (yes, they can be officially downloaded) and found that System.Web.UI.Page.HandleError(Exception e) throws HttpUnhandledException and passes e into its constructor. I expect that InnerException of HttpUnhandledException turns out useful.

Answer 2

You can add this code to your error message:

errorMessage += "\n\n Inner Exception:\n\n" +ex.InnerException;

The InnerException property will give you more details about your error.

I hope it helps!