Question

朋友，我是.NET的新手，我开始在Visual Studio 2017中使用ASP.NET，在为具有角色的用户执行以下JavaScript时遇到问题

<script type='text/javascript'>

        var role = @HttpContext.Current.Session["typeUser"].ToString();

   switch (role){
    case "user" :
           document.getElementByName("Enrollment").disabled = true;
           document.getElementByName("Name").disabled = true;
   break;
}

    </script>

该错误发生在第21行

        var role = @HttpContext.Current.Session["typeUser"].ToString();

描述：执行当前Web请求时出现未处理的异常。检查堆栈跟踪，以获取有关错误及其在代码中起源的详细信息。

运行应用程序时出现以下错误

版本信息：

Microsoft .NET Framework版本：4.0.30319; ASP.NET版本：4.7.3429.0

Stacktrace

[NullReferenceException: Object reference not set to an instance of an object]
       ASP._Page_Views_RegistroTicket_FormTicket_cshtml.<Execute>b__3_0() in C:\Users\User\Desktop\Views\RegistroTicket\FormTicket.cshtml:20
       System.Web.WebPages.<>c__DisplayClass42_0.<RenderSection>b__0(TextWriter tw) +316
       System.Web.WebPages.HelperResult.WriteTo(TextWriter writer) +10
       System.Web.WebPages.WebPageBase.Write(HelperResult result) +80
       ASP._Page_Views_Shared__Layout_cshtml.Execute() in C:\Users\User\Desktop\Views\Shared\_Layout.cshtml:39
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +197
       System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +105
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +90
       System.Web.WebPages.<>c__DisplayClass40_0.<RenderPageCore>b__0(TextWriter writer) +232
       System.Web.WebPages.HelperResult.WriteTo(TextWriter writer) +10
       System.Web.WebPages.WebPageBase.Write(HelperResult result) +80
       System.Web.WebPages.WebPageBase.RenderSurrounding(String partialViewName, Action`1 body) +63
       System.Web.WebPages.WebPageBase.PopContext() +237
       System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +98
       System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +235
       System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +107
       System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +291
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +420
       System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +52
       System.Web.Mvc.Async.<>c__DisplayClass3_6.<BeginInvokeAction>b__3() +198
       System.Web.Mvc.Async.<>c__DisplayClass3_1.<BeginInvokeAction>b__5(IAsyncResult asyncResult) +100
       System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
       System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
       System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
       System.Web.Mvc.<>c.<BeginExecuteCore>b__152_1(IAsyncResult asyncResult, ExecuteCoreState innerState) +11
       System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
       System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
       System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +45
       System.Web.Mvc.<>c.<BeginExecute>b__151_2(IAsyncResult asyncResult, Controller controller) +13
       System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
       System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
       System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
       System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
       System.Web.Mvc.<>c.<BeginProcessRequest>b__20_1(IAsyncResult asyncResult, ProcessRequestState innerState) +28
       System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
       System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
       System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
       System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
       System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9873649
       System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48
       System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +159

如何解决异常是设置会话变量

0 个答案: