All MVC pages fail with the message "An item with the same key has already been added."

[EDN Admin]

Hi there,
Im having a problem with an intermittent issue on one server alone with my application. Every now and then, an app pool will start to fail when trying to load any MVC page with the following error:

Event code: 3005 <br/>
Event message: An unhandled exception has occurred. <br/>
Event time: 10/11/2012 08:09:24 <br/>
Event time (UTC): 10/11/2012 08:09:24 <br/>
Event ID: d76264aedc4241d4bce9247692510466 <br/>
Event sequence: 6407 <br/>
Event occurrence: 30 <br/>
Event detail code: 0 <br/>
<br/>
Application information: <br/>
Application domain: /LM/W3SVC/21/ROOT-2-129969647741292058 <br/>
Trust level: Full <br/>
Application Virtual Path: / <br/>
Application Path: d:websitesFutsal <br/>
Machine name: UKSERVER <br/>
<br/>
Process information: <br/>
Process ID: 6156 <br/>
Process name: w3wp.exe <br/>
Account name: IIS APPPOOLFutsal <br/>
<br/>
Exception information: <br/>
Exception type: ArgumentException <br/>
Exception message: An item with the same key has already been added.<br/>
<br/>
Server stack trace: <br/>
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)<br/>
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)<br/>
at System.Web.WebPages.Scope.WebConfigScopeDictionary.<>c__DisplayClass4.<.ctor>b__0()<br/>
at System.Lazy`1.CreateValue()<br/>
<br/>
Exception rethrown at [0]: <br/>
at System.Lazy`1.get_Value()<br/>
at System.Web.WebPages.Scope.WebConfigScopeDictionary.TryGetValue(Object key, Object& value)<br/>
at System.Web.Mvc.ViewContext.ScopeGet[TValue](IDictionary`2 scope, String name, TValue defaultValue)<br/>
at System.Web.Mvc.ViewContext.ScopeCache.Get(IDictionary`2 scope, HttpContextBase httpContext)<br/>
at System.Web.Mvc.ViewContext.GetClientValidationEnabled(IDictionary`2 scope, HttpContextBase httpContext)<br/>
at System.Web.Mvc.Html.FormExtensions.FormHelper(HtmlHelper htmlHelper, String formAction, FormMethod method, IDictionary`2 htmlAttributes)<br/>
at System.Web.Mvc.Html.FormExtensions.BeginForm(HtmlHelper htmlHelper, String actionName, String controllerName)<br/>
at ASP._Page_Views_Dashboard_Functions_BookingQuickLookup_cshtml.Execute() in d:WebsitesFutsalViewsDashboardFunctionsBookingQuickLookup.cshtml:line 3<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()<br/>
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)<br/>
at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)<br/>
at ASP._Page_Views_Dashboard_Functions_cshtml.Execute() in d:WebsitesFutsalViewsDashboardFunctions.cshtml:line 5<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()<br/>
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)<br/>
at System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(HtmlHelper htmlHelper, String partialViewName, Object model)<br/>
at ASP._Page_Views_Dashboard_Index_cshtml.Execute() in d:WebsitesFutsalViewsDashboardIndex.cshtml:line 9<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()<br/>
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)<br/>
at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)<br/>
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19()<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)<br/>
at System.Web.Mvc.Controller.ExecuteCore()<br/>
at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)<br/>
at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.<BeginProcessRequest>b__5()<br/>
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()<br/>
at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.<EndProcessRequest>b__d()<br/>
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()<br/>
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)<br/>
<br/>
<br/>
<br/>
Request information: <br/>
Request URL: obfuscated<br/>
Request path: /Dashboard <br/>
User host address: 86.164.135.41 <br/>
User: <br/>
Is authenticated: False <br/>
Authentication Type: <br/>
Thread account name: IIS APPPOOLobfuscated <br/>
<br/>
Thread information: <br/>
Thread ID: 17 <br/>
Thread account name: IIS APPPOOLobfuscated <br/>
Is impersonating: False <br/>
Stack trace: at System.Lazy`1.get_Value()<br/>
at System.Web.WebPages.Scope.WebConfigScopeDictionary.TryGetValue(Object key, Object& value)<br/>
at System.Web.Mvc.ViewContext.ScopeGet[TValue](IDictionary`2 scope, String name, TValue defaultValue)<br/>
at System.Web.Mvc.ViewContext.ScopeCache.Get(IDictionary`2 scope, HttpContextBase httpContext)<br/>
at System.Web.Mvc.ViewContext.GetClientValidationEnabled(IDictionary`2 scope, HttpContextBase httpContext)<br/>
at System.Web.Mvc.Html.FormExtensions.FormHelper(HtmlHelper htmlHelper, String formAction, FormMethod method, IDictionary`2 htmlAttributes)<br/>
at System.Web.Mvc.Html.FormExtensions.BeginForm(HtmlHelper htmlHelper, String actionName, String controllerName)<br/>
at ASP._Page_Views_Dashboard_Functions_BookingQuickLookup_cshtml.Execute() in d:WebsitesobfuscatedViewsDashboardFunctionsBookingQuickLookup.cshtml:line 3<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()<br/>
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)<br/>
at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)<br/>
at ASP._Page_Views_Dashboard_Functions_cshtml.Execute() in d:WebsitesobfuscatedViewsDashboardFunctions.cshtml:line 5<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()<br/>
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)<br/>
at System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(HtmlHelper htmlHelper, String partialViewName, Object model)<br/>
at ASP._Page_Views_Dashboard_Index_cshtml.Execute() in d:WebsitesobfuscatedViewsDashboardIndex.cshtml:line 9<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()<br/>
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()<br/>
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)<br/>
at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)<br/>
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19()<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)<br/>
at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)<br/>
at System.Web.Mvc.Controller.ExecuteCore()<br/>
at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)<br/>
at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.<BeginProcessRequest>b__5()<br/>
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()<br/>
at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.<EndProcessRequest>b__d()<br/>
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()<br/>
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)<br/>
<br/>
<br/>
Custom event details: <br/>

Restarting the application pool sorts the problem, but until it is restarted, it happens every time they try to load an MVC page. Asp.net webform pages continue to work fine.

Has anyone seen this issue before?

Thanks for your help.

Matthew





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