Hi

I have implemented an 'EqualTo' Validation Attribute, that compares two Properties of an object, during ModelBinding in ASP.NET MVC 2.

The problem I have is not with it not working, because it does work.

The problem is, when I do my request - which is an ajax request - I get back errors to my front-end, where it sets a class on the input fields to indicate invalid input. What it does is iterate through a list of Errors (in a JsonResult), and set a class.

This is all dandy.

But the ValidationAtrribute I am having trouble with is set at a Class-level, i.e., it's not like other ValidationAttributes where you set something like "[Required]" or something like that.

[AttributeUsage(AttributeTargets.Class, AllowMultiple=true, Inherited=false)]
public class EqualToAttribute : ValidationAttribute
{
    public String SourceProperty { get; set; }
    public String MatchProperty { get; set; }

    public EqualToAttribute(string source, string match)
    {
        SourceProperty = source;
        MatchProperty = match;
    }

    public override Boolean IsValid(Object value)
    {
        Type objectType = value.GetType();

        PropertyInfo[] properties = objectType.GetProperties();

        object sourceValue = new object();
        object matchValue = new object();

        Type sourceType = null;
        Type matchType = null;

        int counter = 0;

        foreach (PropertyInfo propertyInfo in properties)
        {
            if (propertyInfo.Name == SourceProperty || propertyInfo.Name == MatchProperty)
            {
                if (counter == 0)
                {
                    sourceValue = propertyInfo.GetValue(value, null);
                    sourceType = propertyInfo.GetValue(value, null).GetType();
                }
                if (counter == 1)
                {
                    matchValue = propertyInfo.GetValue(value, null);
                    matchType = propertyInfo.GetValue(value, null).GetType();
                }
                counter++;
                if (counter == 2)
                {
                    break;
                }
            }
        }

        if (sourceType != null && matchType != null)
        {
            return sourceValue.ToString().Equals(matchValue.ToString());
            //return Convert.ChangeType(sourceValue, sourceType) == Convert.ChangeType(matchValue, matchType);
        }
        return false;
    }

    private object _typeId = new object();
    public override object TypeId
    {
        get
        {
            return this._typeId;
        }
    }
}

Now this code works, except for the fact that the validation process does not return which Property failed. And I simply can't figure out how to make it return one of the two. In reality I don't care which one it returns.. because both are failing..

Do you have an idea how to make it return the/or both Property/Properties that is/are failing.