How to replace standard DataAnnotations error messages

Question

I\'m using System.ComponontModel.DataAnnotations to validate my model objects. How could I replace messages standard attributes (Required and StringLength) produce without p

Answer 1

For ASP.NET Core validation, refer to this page, where it explains how to set it up using the service engine:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc()
        .AddDataAnnotationsLocalization(options => {
            options.DataAnnotationLocalizerProvider = (type, factory) =>
                factory.Create(typeof(SharedResource));
        });
}

---

Otherwise (WPF, WinForms or .NET Framework), you can use reflection to interfere with the DataAnnotations resources and replace them with your own, which can then be automatically culture-dependent on your app's current culture. Refer to this answer for more:

void InitializeDataAnnotationsCulture()
{
  var sr = 
    typeof(ValidationAttribute)
      .Assembly
      .DefinedTypes
      //ensure class name according to current .NET you're using
      .Single(t => t.FullName == "System.SR");

  var resourceManager = 
    sr
      .DeclaredFields
      //ensure field name
      .Single(f => f.IsStatic && f.Name == "s_resourceManager");

  resourceManager
    .SetValue(null, 
      DataAnnotationsResources.ResourceManager, /* The generated RESX class in my proj */
      BindingFlags.NonPublic | BindingFlags.Static, null, null);

  var injected = resourceManager.GetValue(null) == DataAnnotationsResources.ResourceManager;
  Debug.Assert(injected);
}