Post_16_30.cs

public override void OnActionExecuting(ActionExecutingContext actionExecutingContext)
{
  base.OnActionExecuting(actionExecutingContext);
  this.HandleViewModelMultilingualProperties(actionExecutingContext);
}

private void HandleViewModelMultilingualProperties(ActionExecutingContext actionExecutingContext)
{
  ViewModelBase viewModel = this.GetViewModelFromActionExecutingContext(actionExecutingContext);

  if (viewModel == null)
    return;

  ICultureRepository cultureRepository = this.HttpContext.RequestServices.GetService<ICultureRepository>();

  try
  {
    foreach (PropertyInfo propertyInfo in this.GetLocalizablePropertiesFromViewModel(viewModel))
    {
      this.ModelState.Remove(propertyInfo.Name);

      bool hasRequiredAttribute = propertyInfo.CustomAttributes.Any(ca => ca.AttributeType == typeof(RequiredAttribute));

      foreach (Culture culture in cultureRepository.GetAll())
      {
        string identity = propertyInfo.Name + culture.Code;
        string value = this.Request.Form[identity];

        this.ModelState.SetModelValue(identity, value, value);

        if (hasRequiredAttribute && string.IsNullOrEmpty(value))
        {
          this.ModelState[identity].ValidationState = ModelValidationState.Invalid;
          this.ModelState[identity].Errors.Add(string.Empty);
        }

        else this.ModelState[identity].ValidationState = ModelValidationState.Valid;
      }
    }
  }

  catch { }
}