entity framework 不允许在数据库中保存数据

Question

我在我的应用程序中使用 entityframework codefirst。
我有 2 tables:
1.Order
2.Orderdetails
我想从一个表单中收集数据并在一个操作中将其保存在这 2 table 中。我的表单使用名为 "OrderViewModel".
的视图模型我想在用户单击提交时将数据保存在 "Order" table 和 "Orderdetail" table 中。但我有打击错误：

The model item passed into the dictionary is of type

'Amooshahryar.Models.Order', but this dictionary requires a model item of type 'Amooshahryar.Models.ViewModels.OrderViewModel'.

我的表单使用 'Amooshahryar.Models.ViewModels.OrderViewModel' 并且在 actionresult 中我想按顺序保存数据 table 使用 'Amooshahryar.Models.Order'。
我不明白是什么原因造成的问题。
这是我的代码：

 public ActionResult آدرس_و_پرداخت(FormCollection values)
    {


        var order = new Order() {};

        TryUpdateModel(order);

        int totalcartprice = 0;

        try
        {
            order.Username = User.Identity.Name;
            order.OrderDate = DateTime.Now;
            order.DeliveryStatusID = 1;

            TryUpdateModel(order);

                //Save Order
                db.Orders.Add(order);
                db.SaveChanges(); <===========here i get error

                //Process the order


            //And rest of the code that i havent write here
        }
        catch
        {
            //Invalid - redisplay with errors
            return View(order);
        }
    }

感谢任何帮助...
谢谢你。

编辑：
这是我的堆栈跟踪：

[InvalidOperationException: The model item passed into the dictionary is of type 'Amooshahryar.Models.Order', but this dictionary requires a model item of type 'Amooshahryar.Models.ViewModels.OrderViewModel'.] System.Web.Mvc.ViewDataDictionary1.SetModel(Object value) +378 System.Web.Mvc.ViewDataDictionary.set_Model(Object value) +47 System.Web.Mvc.ViewDataDictionary..ctor(ViewDataDictionary dictionary) +614 System.Web.Mvc.ViewDataDictionary1..ctor(ViewDataDictionary viewDataDictionary) +37 System.Web.Mvc.WebViewPage1.SetViewData(ViewDataDictionary viewData) +98 System.Web.Mvc.WebViewPage.set_ViewData(ViewDataDictionary value) +39 System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +425 System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +382 System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +431 System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +39 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +116 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +529 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList1 filters, ActionResult actionResult) +106 System.Web.Mvc.Async.<>c__DisplayClass2b.b__1c() +321 System.Web.Mvc.Async.<>c__DisplayClass21.b__1e(IAsyncResult asyncResult) +185 System.Web.Mvc.Async.WrappedAsyncResult1.CallEndDelegate(IAsyncResult asyncResult) +42 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +133 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +40 System.Web.Mvc.Controller.b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +34 System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +70 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +133 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37 System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +44 System.Web.Mvc.Controller.b__15(IAsyncResult asyncResult, Controller controller) +39 System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +62 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +133 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +39 System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +39 System.Web.Mvc.MvcHandler.b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +39 System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +70 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +133 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +40 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +38 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9748493 System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +159

Answer 1

这是正在发生的事情：

1) 您的 db.SaveChanges 由于某种原因失败，并抛出异常。

2) 代码因此移动到 Catch 块。

3) 您忽略异常，并尝试执行 return 语句。不幸的是，您的 return 语句也失败了，因为您传递了错误类型的对象。然后这会产生您在屏幕上看到的异常，因为它没有被捕获。

不要像这样压缩异常。如果发生异常，那是因为发生了一些不寻常的事情并且实际上是错误的，所以应用程序崩溃是可以的。不要隐藏它，请始终记录它并进行调查。 Try-catch 用于仅捕获不可避免的异常。数据库崩溃不应该是不可避免的，它应该是不寻常的。此外，如果您在 catch 中的 return 语句确实成功，则用户不会收到有问题的反馈，并且会想知道为什么他们再次出现在同一屏幕上。与此同时，作为开发者，您不会注意到您的应用已损坏

entity framework 不允许在数据库中保存数据

entity framework doesnt allow to save data in db

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