Question

In my project I have a few instances where the user needs to supply an amount (in pounds and pence) as a decimal and it has to be within the Int32 range so it can be converted for the database. I assumed it would be possible to do this:

/// <summary>
/// Range attribute to ensure that entered value can be converted to an int32
/// </summary>
public class PoundsAndPenceAttribute : RangeAttribute
{
    public PoundsAndPenceAttribute(double minimum = (double)int.MinValue / 100, double maximum = (double)int.MaxValue / 100)
        : base(minimum, maximum)
    {
    }
}

Unfortunately it doesn’t produce the client-side JavaScript data-val range attribute, although it does validate it server-side. Is there a better way of doing this or do I have to write a custom validator?

Answer 1

try to implement IClientValidatable interface :

public class PoundsAndPenceeAttribute : RangeAttribute, IClientValidatable
{
    public LocalizeRange(double minimum = (double)int.MinValue / 100, double maximum = (double)int.MaxValue / 100) 
: base(minimum, maximum)
    {
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        var rule = new ModelClientValidationRule
        {
            ErrorMessage = ErrorMessage,
            ValidationType = "range"
        };

        rule.ValidationParameters.Add("min", Minimum);
        rule.ValidationParameters.Add("max", Maximum);

        yield return rule;
    }
}

It should do the job.