Model Validation / ASP.NET MVC 3 - Conditional Required Attribute

Question

I\'m having trouble with my ASP.NET MVC 3 application. I have 2 propertiesin my model whereby I only want 1 of them required in my view based on whichever one is empty. So f

Answer 1

You can implement IValidatableObject on your class and provide a Validate() method that implements your custom logic. Combine this with custom validation logic on the client if you prefer to ensure that one is supplied. I find this easier than implementing an attribute.

public class ContactModel : IValidatableObject
{
   ...

   public IEnumerable Validate( ValidationContext context )
   {
        if (string.IsNullOrWhitespace( ContactPhoneNumber ) 
            && string.IsNullOrWhitespace( ContactEmailAddress ))
        {
             yield return new ValidationResult( "Contact Phone Number or Email Address must be supplied.", new [] { "ContactPhoneNumber", "ContactEmailAddress" } );
        }
   }
}

To get everything working at client side you'll need to add the following script to your view: