ModelState.AddModelError NullReferenceException (ASP.Net MVC Validations)



While trying to add validation errors to the ModelState using the AddModelError method, I was getting “NullReferenceException” run time errors.

After doing some research I found that if we follow the AddModelError with SetModelValue method as shown by the highlighted line below, the system doesn’t throw runtime NullReferenceException anymore.

ModelState.AddModelError(PropertyName, ErrorMessage);
ModelState.SetModelValue(PropertyName,ValueProvider[PropertyName]);

Comments

Post a Comment

Popular posts from this blog

WPF How to Dispose ViewModel when the associated UserControl (Not Window) closes?

Note: If your WPF UserControl is hosted in MFC Window, you may want to clean-up the ViewModel that is DataContext of your UserControl. Since Unloaded event is not called reliably for the UserControl when the hosting MFC Window closes, there is a need for another solution. XAML: < UserControl  x : Class = "Views.MyUserControl"               xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"               xmlns : x = "http://schemas.microsoft.com/winfx/2006/xaml"               xmlns : mc = "http://schemas.openxmlformats.org/markup-compatibility/2006"                 xmlns : d = "http://schemas.microsoft.com/expression/blend/2008"                 mc : Ignorable = "d"                 d : DesignHeight = "300"  d : DesignWidth = "300" >      < Grid >                   </ Grid > </ UserControl > Code Behind: using  System; using  ViewModels; name
Read more

C# How to unit test Dispatcher

Dispatcher provides services for managing the queue of work items for a thread. Sometimes to execute a task on a background thread.  Any task executed by calling Dispatcher.BeginInvoke(...) in unit test does not get executed until you do some wire-up. This is how you would unit test code with Dispatcher. using  System; using  System.Windows.Threading; using  Microsoft.VisualStudio.TestTools.UnitTesting; namespace  UnitTesting.Tests {     [ TestClass ]      public   class   DispatcherUtilTest     {          private   ClassThatUsesDispatcher  _subject;         [ TestInitialize ]          public   void  TestInitialize()         {             _subject =  new   ClassThatUsesDispatcher ();         }         [ TestMethod ]          public   void  UseDispatcher()         {              // Arrange              var  backgroundWorkDone =  false ;             _subject.BackgroungWorkAction = () => { backgroundWorkDone =  true ; };              // Act             _subject.DoWork(
Read more

WPF: How to Deep Copy WPF object (e.g. UIElement) ?

         ///  Generic Method to perform Deep-Copy of a WPF element (e.g. UIElement)          public   static  T DeepCopy (T element)         {              var  xaml =  XamlWriter .Save(element);              var  xamlString =  new   StringReader (xaml);              var  xmlTextReader =  new   XmlTextReader (xamlString);              var  deepCopyObject = (T) XamlReader .Load(xmlTextReader);              return  deepCopyObject;         }          ///  Test showing that the deep copied object does not have the same reference as the object being copied         [ TestMethod ]          public   void  DeepCopy()         {              // Arrange              Shape  shape =  new   Rectangle  {Fill =  new   SolidColorBrush ( Colors .Red)};              // Act              var  deepCopyShape =  MyClass .DeepCopy(shape);              // Assert              Assert .AreNotSame(shape, deepCopyShape);         }  
Read more