System.FormatException：输入字符串的格式不正确。 MVC5

Question

这是我的代码：

string idString = System.Web.HttpContext.Current.User.Identity.Name; 
int customerID = int.Parse(idString);

Customer customer = db.Customers.SingleOrDefault(c => c.CustomerID == customerID);
customer.FirstName = cart.BillingInfo.FirstName;
customer.LastName = cart.BillingInfo.LastName;
customer.BillingAddress = cart.BillingInfo.Address;
customer.BillingCity = cart.BillingInfo.City;
customer.BillingState = cart.BillingInfo.State;
customer.BillingPostalCode = cart.BillingInfo.Zip;
customer.CardNumber = cart.BillingInfo.CreditCardNumber;
customer.ExpirationMonth = cart.BillingInfo.ExpirationMonth;
customer.ExpirationYear = cart.BillingInfo.ExpirationYear;

db.SaveChanges();

我收到此错误：

“/”应用程序中的服务器错误。

输入字符串的格式不正确。

说明：在执行当前 Web 请求期间发生未处理的异常。请查看堆栈跟踪以获取有关错误及其源自代码的位置的更多信息。

异常详细信息：System.FormatException：输入字符串格式不正确。

来源错误：

在执行当前 Web 请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪来识别有关异常起源和位置的信息。

堆栈跟踪：

[FormatException: Input string was not in a correct format.]
   System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +11174263
   System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +145
   System.Int32.Parse(String s) +23
   DJMaxStore.Controllers.ShoppingCartController.ProcessOrder(ShoppingCartModel cart) in c:\Users\irosario\Desktop\DJMaxStore\DJMaxStore\Controllers\ShoppingCartController.cs:109
   DJMaxStore.Controllers.ShoppingCartController.BillingInfo(BillingInfo billingInfo) in c:\Users\irosario\Desktop\DJMaxStore\DJMaxStore\Controllers\ShoppingCartController.cs:96
   lambda_method(Closure , ControllerBase , Object[] ) +180
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +59
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +434
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +60
   System.Web.Mvc.Async.ActionInvocation.InvokeSynchronousActionMethod() +76
   System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +36
   System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +73
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +136
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +102
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +49
   System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +117
   System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +323
   System.Web.Mvc.Async.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) +44
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +47
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +136
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +102
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +50
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +72
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +185
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +42
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.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.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +34
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +139
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +59
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +40
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +44
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +62
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +139
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +59
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +40
   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.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +139
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +59
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +40
   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() +9650772
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

版本信息：Microsoft .NET Framework 版本：4.0.30319； ASP.NET 版本：4.0.30319.36283

Answer 1

看起来像 System.Int32.Parse(String s)（在 ShoppingCartController.ProcessOrder 方法内） 接受无效的论点。检查传递给该方法的内容。这是一个整数吗？

编辑：

您正在尝试将字符串转换为整数。如果idString 的格式不正确（不是数字），那么您将得到System.FormatException。请参阅：https://msdn.microsoft.com/pl-pl/library/b3h1hf19(v=vs.110).aspx。

Answer 2

这是因为您正在尝试解析无法转换为整数的字符串。使用int.TryParse()方法

 int myInt;
 var result = int.TryParse("23", out myInt);

 if (result == true)
 {
    // do something...
 }