Client side validation for custom annotation Asp.Net MVC 4

Question

I am referring this article:

http://haacked.com/archive/2009/11/19/aspnetmvc2-custom-validation.aspx

which shows how to create custom annotation in Asp.Net MVC 2

Answer 1

The key thing missing here is that the server-side validator must implement the IClientValidatable interface:

public class RateRequiredIfCustomIndexRateAttribute : ValidationAttribute, IClientValidatable
{
    public override bool IsValid(object value)
    {
        return false;
    }

    public IEnumerable GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        yield return new ModelClientValidationRule
        {
            ErrorMessage = this.ErrorMessage,
            ValidationType = "raterequiredifcustomindexrate"
        };
    }
}

Once you do that, the client-side validation should be hooked up properly. You can verify this by making sure that your input field has an attribute "data-val-raterequiredifcustomindexrate" attribute.