Object reference not set to an instance of an object RSS

• • Reply
  marymary

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  0 Points

  1 Post

  Object reference not set to an instance of an object

  Feb 27, 2019 02:06 PM|marymary|LINK

  Hi!

  I'm developing SQL Server Database and it's connected with c# app. Now  I'm having a problem with saving data to database. Can you figure it out why? Thanks!

  Web.Main Code

  [SoapDocumentMethod("http://tempuri.org/Main", ParameterStyle = SoapParameterStyle.Wrapped, RequestNamespace = "http://tempuri.org/", ResponseNamespace = "http://tempuri.org/", Use = SoapBindingUse.Literal)]
  public DataSet Main(
  [XmlElement(IsNullable = true)] int? A,
  string B,
  [XmlElement(IsNullable = true)] int? C,
  string D,
  string E,
  string connstring)
  {
  return (DataSet) this.Invoke(nameof (Main), new object[41]
  {
  (object) A,
  (object) B,
  (object) C,
  (object) D,
  (object) E,
  (object) connstring
  })[0];
  }

  WebService.SaveChanges

  public Result SaveChanges(
  something model,
  string username,
  int status)
  {
  Result result = new Result();
  string empty = string.Empty;
  if (model.number >= 0)
  empty = Convert.ToString(model.number);
  
  DataSet dataSet = this.Main(model.M,  model.N, model.O, model.P, status, new DateTime?(DateTime.Now), new DateTime?(), model.R, model.S,  model.T, true, new DateTime?(DateTime.Now), new DateTime?(), new DateTime?(DateTime.Now), username, Configuration.ConnectionString);
  if (!dataSet.Tables[0].Rows[0]["Error"].Equals((object) 0))
  return result;
  }

  Stack Trace:

  [NullReferenceException: Object reference not set to an instance of an object.]
     System.Web.Services.Protocols.SoapHttpClientProtocol.Serialize(SoapClientMessage message) 
     System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) 
     Web.Main(Nullable`1 A, String B, Nullable`1 C, String D, String E, String F, String connstring) 
     WebService.SaveChanges(something model, String username, Int32 status) 
     Web.Controllers.Save(something model) 
     lambda_method(Closure , ControllerBase , Object[] ) 
     System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) 
     System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +34
     System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +32
     System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +41
     System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +79
     System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +387
     System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +42
     System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +32
     System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +187
     System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +38
     System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +27
     System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +25
     System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +52
     System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +25
     System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +38
     System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +41
     System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +25
     System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +38
     System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +602
     System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
     System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +128

• • Reply
  PaulTheSmith

  Participant

  1660 Points

  952 Posts

  Re: Object reference not set to an instance of an object

  Feb 27, 2019 09:30 PM|PaulTheSmith|LINK

  I'm not really a SOAP person but I'll have a go.

  The method called Main has a single statement which returns the first element of the result of a call to this.Invoke.

  The first parameter to Invoke is the name of the method you wish to call.  That name is Main.

  So Main is calling itself and passing the parameters it was called with.  This would seem to be an infinite loop

  It doesn't seem likely to me that this code would compile as you are trying to create an array with 41 elements but the initializer is only six elements long.  I would expect the compiler to say

  CS0847 An array initializer of length '41' is expected.

  Can you explain a bit more about what you are trying to do as this doesn't seem to make any sense at al?.  And it is not valid code.

  It looks like you have an actual runtime Exception which means that you must have code that compiles.  Can you create a small sample of code which anyone can run which demonstrates your problem?

• • Reply
  Ackerly Xu

  Contributor

  3500 Points

  1300 Posts

  Re: Object reference not set to an instance of an object

  Feb 28, 2019 07:16 AM|Ackerly Xu|LINK

  Hi marymary,

  The problem may be with your code 

  dataSet.Tables[0].Rows[0]["Error"].Equals((object) 0)

  Debug to see whether  any of  dataSet,Tables[0], Rows[0] ["Error"] is null.

  Best regards,

  Ackerly Xu

  MSDN Community Support
  Please remember to click "Mark as Answer" the responses that resolved your issue.
  If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.
• • Reply
  lingmaaki

  Member

  20 Points

  22 Posts

  Re: Object reference not set to an instance of an object

  Mar 05, 2019 04:53 AM|lingmaaki|LINK

  The message "Object not set to instance of Object" means that you are trying to use an object which has not been initialized. That is, you either set it to null, or you never set it to anything at all. The runtime throwing a NullReferenceException always means the same thing: you are trying to use a reference. The reference is not initialized (or it was initialized, but is no longer initialized).