I am seeing a very sporadic error when users log into an MVC 5 app. It only happens once every 100 or so logins and only happens on a remote web server. When it occurs users cannot login, however, if we recycle the app pool the error goes away and everyone can login again.
Exception information:
Exception type: ArgumentNullException
Exception message: Value cannot be null.
Parameter name: source
at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
at ASP._Page_Views_Shared__LoginPartial_cshtml.Execute() in c:\inetpub\wwwroot\appname\Views\Shared\_LoginPartial.cshtml:line 18
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)
at ASP._Page_Views_Shared__Layout_cshtml.Execute() in c:\inetpub\wwwroot\appname\Views\Shared\_Layout.cshtml:line 42
According to the above the error occurs in the LoginPartial.cshtml which is from the MVC 5 VS template but I cannot find anything there that would cause this and it doesn't make sense why this happens so sporadically and then recycling the app pool fixes it.
@model POC.Web.Models.LoginViewModel
@{ ViewBag.Title = "Log in"; }
<h2>@ViewBag.Title</h2>
<div class="row">
<div class="col-md-12">
<section id="loginForm">
@using (Html.BeginForm("Login", "Account", new { ReturnUrl = ViewBag.ReturnUrl }, FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
@Html.AntiForgeryToken()
<hr />
@Html.ValidationSummary(true)
<div class="form-group">
@Html.LabelFor(m => m.UserName, new { @class = "col-md-2 control-label" })
<div class="col-md-10">
@Html.TextBoxFor(m => m.UserName, new { autocomplete = "off", @class = "form-control" })
@Html.ValidationMessageFor(m => m.UserName)
</div>
</div>
<div class="form-group">
@Html.LabelFor(m => m.Password, new { @class = "col-md-2 control-label" })
<div class="col-md-10">
@Html.PasswordFor(m => m.Password, new { @class = "form-control" })
@Html.ValidationMessageFor(m => m.Password)
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<div class="checkbox">
@Html.CheckBoxFor(m => m.RememberMe)
@Html.LabelFor(m => m.RememberMe)
</div>
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Log in" class="btn btn-default" />
</div>
</div>
}
</section>
</div>
</div>
@section Scripts {
@Scripts.Render("~/bundles/jqueryval")
}
Found the issue, it was in a different view(LoginPartial) than the above(Login). Data was null in the cache.
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