redirect - 添加列表并重定向到另一个 View 时，Asp.net 核心 TempData 给出 500 错误

Question

我正在尝试建立警报列表并将它们添加到 TempData .但如果我没有做重定向，它就可以工作。当我重定向时，它会给我 500 错误。我也在 View 中设置了断点，但是当重定向时它没有命中，否则它正确命中。

Action 方法

public IActionResult Create(CategoryCreateVM input)
{
    if (ModelState.IsValid)
    {
        var category = mapper.Map<Categories>(input);
        categoryBL.Add(category);

        List<Alert> alert = new List<Alert>();
        alert.Add(new Alert("alert-success", "success message"));
        alert.Add(new Alert("alert-danger", "danger message"));

        TempData["Alert"] = alert;

        return RedirectToAction("Index");
    }
    return View(input);
}

我如何访问 View 。

@{ 
    var alerts = TempData["Alert"] as List<Alert>;
}
@if (alerts != null && alerts.Count > 0)
{
    <div class="">
        @foreach (var alert in alerts)
        {
            <div class="alert @alert.AlertClass alert-dismissible">
                <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
                @alert.Message
            </div>

        }
    </div>

}

堆栈跟踪。

    Exception thrown: 'System.InvalidOperationException' in Microsoft.AspNetCore.Mvc.ViewFeatures.dll
Exception thrown: 'System.InvalidOperationException' in mscorlib.dll
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker: Information: Executed action MvcSandbox.Controllers.HomeController.Index (MvcSandbox) in 46.4619ms
Exception thrown: 'System.InvalidOperationException' in mscorlib.dll
Exception thrown: 'System.InvalidOperationException' in mscorlib.dll
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware: Error: An unhandled exception has occurred while executing the request

System.InvalidOperationException: The 'Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.TempDataSerializer' cannot serialize an object of type 'MvcSandbox.Controllers.Alert'.
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.TempDataSerializer.EnsureObjectCanBeSerialized(Object item) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\TempDataSerializer.cs:line 207
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.TempDataSerializer.Serialize(IDictionary`2 values) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\TempDataSerializer.cs:line 142
   at Microsoft.AspNetCore.Mvc.ViewFeatures.SessionStateTempDataProvider.SaveTempData(HttpContext context, IDictionary`2 values) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\ViewFeatures\SessionStateTempDataProvider.cs:line 62
   at Microsoft.AspNetCore.Mvc.ViewFeatures.TempDataDictionary.Save() in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\ViewFeatures\TempDataDictionary.cs:line 166
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.SaveTempDataFilter.SaveTempData(IActionResult result, ITempDataDictionaryFactory factory, HttpContext httpContext) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\SaveTempDataFilter.cs:line 91
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.SaveTempDataFilter.OnResultExecuted(ResultExecutedContext context) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\SaveTempDataFilter.cs:line 80
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.Core\Internal\ControllerActionInvoker.cs:line 1023
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextResourceFilter>d__22.MoveNext() in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.Core\Internal\ControllerActionInvoker.cs:line 1105
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ResourceExecutedContext context) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.Core\Internal\ControllerActionInvoker.cs:line 1377
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.Core\Internal\ControllerActionInvoker.cs:line 493
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__20.MoveNext() in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.Core\Internal\ControllerActionInvoker.cs:line 164
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at Microsoft.AspNetCore.Session.SessionMiddleware.<Invoke>d__9.MoveNext() in D:\temp\Session-dev\Session-dev\src\Microsoft.AspNetCore.Session\SessionMiddleware.cs:line 106
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Session.SessionMiddleware.<Invoke>d__9.MoveNext() in D:\temp\Session-dev\Session-dev\src\Microsoft.AspNetCore.Session\SessionMiddleware.cs:line 123
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()
Exception thrown: 'System.InvalidOperationException' in Microsoft.AspNetCore.Http.dll
Microsoft.AspNetCore.Server.Kestrel: Error: Connection id "0HL1I8OFS17SU": An unhandled exception was thrown by the application.

System.InvalidOperationException: Session has not been configured for this application or request.
   at Microsoft.AspNetCore.Http.DefaultHttpContext.get_Session()
   at Microsoft.AspNetCore.Mvc.ViewFeatures.SessionStateTempDataProvider.SaveTempData(HttpContext context, IDictionary`2 values) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\ViewFeatures\SessionStateTempDataProvider.cs:line 57
   at Microsoft.AspNetCore.Mvc.ViewFeatures.TempDataDictionary.Save() in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\ViewFeatures\TempDataDictionary.cs:line 166
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.SaveTempDataFilter.SaveTempData(IActionResult result, ITempDataDictionaryFactory factory, HttpContext httpContext) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\SaveTempDataFilter.cs:line 91
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.SaveTempDataFilter.<>c.<OnResultExecuting>b__5_0(Object state) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\SaveTempDataFilter.cs:line 57
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame.<FireOnStarting>d__178.MoveNext()
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware: Error: An exception was thrown attempting to display the error page.

System.ObjectDisposedException: The response has been aborted due to an unhandled application exception. ---> System.InvalidOperationException: Session has not been configured for this application or request.
   at Microsoft.AspNetCore.Http.DefaultHttpContext.get_Session()
   at Microsoft.AspNetCore.Mvc.ViewFeatures.SessionStateTempDataProvider.SaveTempData(HttpContext context, IDictionary`2 values) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\ViewFeatures\SessionStateTempDataProvider.cs:line 57
   at Microsoft.AspNetCore.Mvc.ViewFeatures.TempDataDictionary.Save() in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\ViewFeatures\TempDataDictionary.cs:line 166
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.SaveTempDataFilter.SaveTempData(IActionResult result, ITempDataDictionaryFactory factory, HttpContext httpContext) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\SaveTempDataFilter.cs:line 91
   at Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.SaveTempDataFilter.<>c.<OnResultExecuting>b__5_0(Object state) in D:\temp\Mvc-dev\src\Microsoft.AspNetCore.Mvc.ViewFeatures\Internal\SaveTempDataFilter.cs:line 57
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame.<FireOnStarting>d__178.MoveNext()
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame.ThrowResponseAbortedException()
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame.<ProduceStartAndFireOnStartingAwaited>d__194.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame.Write(ArraySegment`1 data)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.FrameResponseStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.StreamWriter.Flush(Boolean flushStream, Boolean flushEncoder)
   at System.IO.StreamWriter.Write(String value)
   at Microsoft.Extensions.RazorViews.BaseView.Write(String value)
   at Microsoft.AspNetCore.Diagnostics.RazorViews.ErrorPage.<ExecuteAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Extensions.RazorViews.BaseView.<ExecuteAsync>d__29.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()
Microsoft.AspNetCore.Server.Kestrel: Error: Connection id "0HL1I8OFS17SU": An unhandled exception was thrown by the application.

Answer 1

最后，我在深入研究源代码后弄清楚了问题所在。 Asp.Net Core MVC不支持 TempData 的复杂数据类型现在。仅支持string目前。它在序列化数据时通过这个异常，如果我们通过其他然后 string .

The 'Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.TempDataSerializer' cannot serialize an object of type 'MvcSandbox.Controllers.Alert'.

我将我的列表序列化为 json，然后保存在 TempData .

这是我如何做到的。我创建了扩展方法来从 TempData 添加和检索数据.

const string Alerts = "Alerts";
public static List<Alert> GetAlert(this ITempDataDictionary tempData)
{
    CreateAlertTempData(tempData);
    return DeserializeAlerts(tempData[Alerts] as string);
}

public static void CreateAlertTempData(this ITempDataDictionary tempData)
{
    if (!tempData.ContainsKey(Alerts))
    {
        tempData[Alerts] = "";
    }
}
public static void AddAlert(this ITempDataDictionary tempData, Alert alert)
{
    if(alert == null)
    {
        throw new ArgumentNullException(nameof(alert));
    }
    var deserializeAlertList = tempData.GetAlert();
    deserializeAlertList.Add(alert);
    tempData[Alerts] = SerializeAlerts(deserializeAlertList);
}
public static string SerializeAlerts(List<Alert> tempData)
{
    return JsonConvert.SerializeObject(tempData);
}
public static List<Alert> DeserializeAlerts(string tempData)
{
    if(tempData.Length == 0)
    {
        return new List<Alert>();
    }
    return JsonConvert.DeserializeObject<List<Alert>>(tempData);
}

添加提醒它 TempData

 tempData.AddAlert(new Alert(AlertClass, Message));

最后得到 'TempData in查看'和显示。

@if (TempData.GetAlert().Count > 0)
{
    <div class="alert-container">
        @foreach (var alert in TempData.GetAlert())
        {
            <div class="alert @alert.AlertClass alert-dismissible">
                <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
                @alert.Message
            </div>
        }
    </div>
}