xVal - MVC: add a validation to all properties of a type

Question

I have a MVC website with a complex model. I'm using xVal to do my validation by decorating my model properties with validation attributtes.

I'm looking for at way to add a StringLengthRule to all properties of type string without manually adding a StringLengthAttributte to all the properties.

One way to go was to make my own IRulesProvider as shown here:

public class TODO_MyRulesProvider : IRulesProvider
    {
        public RuleSet GetRulesFromType(Type type)
        {
            Dictionary<string,Rule> myRules = new Dictionary<string, Rule>();

            foreach (var property in type.GetProperties())
            {
                if(property.PropertyType == typeof(string))
                {
                    var rule = new StringLengthRule(0, 255);
                    myRules[property.Name] = rule;
                }
            }



            ILookup<string, Rule> rules = myRules.ToLookup(o => o.Key, o => o.Value);

            return new RuleSet(rules);
        }
    }


protected void Application_Start()
        {
xVal.ActiveRuleProviders.Providers.Add(new TODO_MyRulesProvider());
}

With this approach I can get it to work, but the method GetRulesFromType is called once per property, which gives med json code like this in the html:

{"RuleName":"Custom","RuleParameters":{"Function":"RegExValidate","Parameters":"{\"regEx\":\"^\\\\w+$\"}"}},
{"RuleName":"StringLength","RuleParameters":{"MinLength":"0","MaxLength":"255"}},
{"RuleName":"StringLength","RuleParameters":{"MinLength":"0","MaxLength":"255"}},
{"RuleName":"StringLength","RuleParameters":{"MinLength":"0","MaxLength":"255"}},
{"RuleName":"StringLength","RuleParameters":{"MinLength":"0","MaxLength":"255"}},
{"RuleName":"StringLength","RuleParameters":{"MinLength":"0","MaxLength":"255"}}

How can I accomplish my goal?