Using DataAnnotations to compare two model properties

Question

How would I go about writing a custom ValidationAttribute that compares two fields? This is the common \"enter password\", \"confirm password\" scenario. I need to be sure t

Answer 1

This is a longer version of Darin's answer:

public class CustomAttribute : ValidationAttribute
{    
    public override bool IsValid(object value)
    {
        if (value.GetType() == typeof(Foo))
        {
           Foo bar = (Foo)value;
           //compare the properties and return the result
        }

        throw new InvalidOperationException("This attribute is only valid for Foo objects");
    }
}

and usage:

[MetadataType(typeof(FooMD))]
public partial class Foo
{
     ... functions ...
}

[Custom]
public class FooMD
{
     ... other data annotations ...
}

The error will display in @Html.ValidationSummary(false)