Custom ValidationAttribute doesn't work

Question

I tried to create a custom ValidationAttribute:

public class RollType : ValidationAttribute
{
    public override bool IsValid(object value)
    {
        return false;   // just for trying...
    }
}

Then I created (in another class) -

  [RollType]
  [Range(0,4)]
  public int? Try { get; set; }

on the view (I use MVC) I wrote:

      <div class="editor-label">
            Try:
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Try)
            @Html.ValidationMessageFor(model => model.Try)
        </div>

The validation for "range" works great, but not for the custom one!

What can be the problem?

Frow

Note that RollTypeAttribute is the recommended name for this class. You can still use [RollType] with that new name. – Millionaire

Answer 1

Try this

public class RollType : ValidationAttribute
{
   protected override ValidationResult IsValid(object value, ValidationContext validationContext)
   {
      return new ValidationResult("Something went wrong");
   }
}

Also do not forget to check if modelstate is valid in code behind or else it won't work, Example

    [HttpPost]
    public ActionResult Create(SomeObject object)
    {
        if (ModelState.IsValid)
        {
            //Insert code here
            return RedirectToAction("Index");
        }
        else
        {
            return View();
        }
    }

Sketchy

"Error 1 'RollType.IsValid(object, System.ComponentModel.DataAnnotations.ValidationContext)': cannot change access modifiers when overriding 'protected' inherited member 'System.ComponentModel.DataAnnotations.ValidationAttribute.IsValid(object, System.ComponentModel.DataAnnotations.ValidationContext)' " – Frow

Sorry I just fixed the mistake, it need to be protected override not public override, it will work now. – Sketchy

Also if you want to ass a success message use 'return ValidationResult.Success;' – Sketchy

Thanks! I deleted everything I did and start from begining and used your code and now it works.. :) – Frow