C# Azure移动服务：InsertAsync异常

我正在尝试从Xamarin应用程序插入windows Azure移动服务数据库。插页很好用。但我得到以下例外

我看到了一些与以下链接相关的问题。但还是不能让它为我工作

Exception=System.NullReferenceException:对象引用未设置为对象的实例。
在xPlatAuction.Backend.Controllers.BidController.d_u0.MoveNext（）上
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Threading.Tasks.TaskHelperExtensions.d_u3`1.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Web.Http.Controllers.ApiControllerActionInvoker.d_u0.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Web.Http.Filters.ActionFilterAttribute.d_u5.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
在System.Web.Http.Filters.ActionFilterAttribute.d_u5.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Web.Http.Filters.ActionFilterAttribute.d_u0.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Web.Http.Controllers.ActionFilterResult.d_u2.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Web.Http.Filters.AuthorizationFilterAttribute.d_u2.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在System.Web.Http.Controllers.AuthenticationFilterResult.d__0.MoveNext（）中
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
位于System.Web.Http.Controllers.ExceptionFilterResult.d_u0.MoveNext（），Id=855e229d-5653-45c3-9e9a-178a3aea5244，Category='App.Filters'

您提到的异常日志，它可能遗漏了一些抛出空引用的I/p参数，插入同步方法以前工作正常

您没有提到您提供的输入，请查找错误所在的一些区域：

当您开发跨平台应用程序时（使用Xamarin，即您可能正在开发Android、IOS或Windows应用程序，并与Azure移动服务交互）。所以可能有

输入URL将被删除。您也可以使用（此插入同步方法以前也可以正常工作）

你也可以看看下面的问题：

Exception=System.NullReferenceException: Object reference not set to an instance of an object.
   at xPlatAuction.Backend.Controllers.BidController.<PostBid>d__0.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.Threading.Tasks.TaskHelpersExtensions.<CastToObject>d__3`1.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.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.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.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.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.Web.Http.Filters.ActionFilterAttribute.<ExecuteActionFilterAsyncCore>d__0.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.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.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.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.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.Web.Http.Controllers.AuthenticationFilterResult.<ExecuteAsync>d__0.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.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext(), Id=855e229d-5653-45c3-9e9a-178a3aea5244, Category='App.Filters'