可為空對象的異常信息

Question

我有一個具有某些屬性的對象。 我通過對象初始值設定項初始化一個對象。

對象初始化后，我得到這個異常

 System.NullReferenceException: Object reference not set to an instance of an object.
       at Web.Admin.Models.UserModel.<>c__DisplayClass0_1.<LoadData>b__7(<>f__AnonymousType8`2 <>h__TransparentIdentifier1) in D:\Builds\agent1\1610\s\Web.Admin\Models\UserModel.cs:line 61
       at System.Linq.Enumerable.WhereSelectListIterator`2.MoveNext()
       at System.Collections.Generic.List`1.InsertRange(Int32 index, IEnumerable`1 collection)
    at Web.Admin.Models.UserModel.<LoadData>d__0.MoveNext() in D:\Builds\agent1\1610\s\Web.Admin\Models\UserModel.cs:line 56
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Web.Admin.Controllers.Api.UserController.<Get>d__2.MoveNext() in D:\Builds\agent1\1610\s\Web.Admin\Controllers\Api\UserController.cs:line 41
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.TaskHelpersExtensions.<CastToObject>d__1`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    
   at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__1.MoveNext()    
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__6.MoveNext() [] 

我想找到一個空對象，我嘗試初始化對象的屬性。 我無法使用生產數據進行調試。 我可以從這個異常中讀取一些信息嗎？ 例如，我嘗試從空對象初始化的屬性索引？ 或者什么東西可以幫助我？

對不起，我的英語不好。 謝謝

Answer 1

這個異常並沒有告訴我們哪個屬性/變量導致了NullReferenceException 。 但是我們可以看到它在UserController.cs第 41 行被拋出。

您唯一的做法是在UserController.cs第 41 行設置斷點並檢查該行上使用的每個變量的值。