asp.net-mvc-3 - asp.net 会员资格在生产中失败

Question

我有一个使用 ASP.NET Membership 的 ASP.NET MVC 3 应用程序。我在生产环境中遇到奇怪的错误。一位客户抱怨说，他们在尝试使用 Chrome 登录时总是会出错。它适用于 IE。然而，对于另一个客户端，当他们使用 IE 登录但在 Chrome 中工作时，他们会遇到同样的错误。

这是登录的代码

[HttpPost]
    public ActionResult LogOn(LogOnModel model, string returnUrl)
    {
        if (ModelState.IsValid)
        {
            if (Membership.ValidateUser(model.UserName, model.Password))
            {
                FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
                if (Url.IsLocalUrl(returnUrl) && returnUrl.Length > 1 && returnUrl.StartsWith("/")
                    && !returnUrl.StartsWith("//") && !returnUrl.StartsWith("/\\"))
                {
                    if (returnUrl.Contains("CorporaClaim"))
                        ViewBag.Layout = _corporaLayout;
                    else
                        ViewBag.Layout = _layout;
                    return Redirect(returnUrl);
                }
                else
                {
                    ViewBag.Layout = _layout;
                    // redirect user according to user role
                    if (!string.IsNullOrEmpty(model.UserName))
                        return RedirectToDentalinkActionBasedOnRole(model.UserName);
                }
            }
            else
            {
                ModelState.AddModelError("", "The user name or password provided is incorrect.");
            }
        }
        ViewBag.Layout = _layout;
        // If we got this far, something failed, redisplay form
        return View(model);
    }

在我的 _Layout.cshtml 中，我调用了以下方法以显示登录用户的名称：

@{

string displayName = DentalinkWeb.Utility.LoginUtility.GetDisplayForUser(User);

}

public class LoginUtility
{
    public static string GetDisplayForUser(IPrincipal User)
    {
        string displayName = "";
        if (User.Identity.IsAuthenticated)
        {                
            if (User.IsInRole("Practice Admin"))
            {
                DentalinkEntities db = new DentalinkEntities();
                RegisteredPractice prac = (from p in db.RegisteredPractices where p.Email == User.Identity.Name select p).FirstOrDefault();
                displayName = prac.DentistFirstName + " " + prac.DentistSurname;
            }
            else if (User.IsInRole("Dentalink Admin"))
            {
                displayName = "Dentalink Admin";

            }

        }
        return displayName;
    }

}

}

我们得到这个错误：

System.NullReferenceException: Object reference not set to an instance of an object.
   at DentalinkWeb.Utility.LoginUtility.GetDisplayForUser(IPrincipal User)
   at ASP._Page_Views_Shared__Layout_cshtml.Execute() in e:\web\dentalinkco\htdocs\Views\Shared\_Layout.cshtml:line 51
   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.WebPages.WebPageBase.<>c__DisplayClass7.<RenderPageCore>b__6(TextWriter writer)
   at System.Web.WebPages.HelperResult.WriteTo(TextWriter writer)
   at System.Web.WebPages.WebPageBase.Write(HelperResult result)
   at System.Web.WebPages.WebPageBase.RenderSurrounding(String partialViewName, Action`1 body)
   at System.Web.WebPages.WebPageBase.PopContext()
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   at System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance)
   at System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer)
   at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)
   at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)
   at System.Web.Mvc.Controller.ExecuteCore()
   at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)
   at System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext)
   at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.<BeginProcessRequest>b__5()
   at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()
   at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End()
   at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.<EndProcessRequest>b__d()
   at System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f)
   at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action)
   at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
   at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

请帮忙。

Answer 1

Here's a revised code.

public class LoginUtility
{
    public static string GetDisplayForUser(IPrincipal User)
    {
        string displayName = "";
        if (User != null)
        {
            if (User.Identity.IsAuthenticated)
            {                
                if (User.IsInRole("Practice Admin"))
                {
                    DentalinkEntities db = new DentalinkEntities();
                    RegisteredPractice prac = (from p in db.RegisteredPractices where p.Email == User.Identity.Name select p).FirstOrDefault();
                    displayName = prac.DentistFirstName + " " + prac.DentistSurname;
                }
                else if (User.IsInRole("Dentalink Admin"))
                {
                    displayName = "Dentalink Admin";
                }
            }
        }
        return displayName;
    }
}

Answer 2

我唯一能想到的就是添加User != nullif 语句。

if (User != null && User.Identity.IsAuthenticated)
{
  ...

  RegisteredPractice prac = (from p in db.RegisteredPractices 
          where p.Email == User.Identity.Name select p).FirstOrDefault();
  if(prac != null) // Just to be on safe side.
  {
     displayName = prac.DentistFirstName + " " + prac.DentistSurname;
  }

  ...

}