Restrict the use of an attribute validation (ValidationAttribute ) for only one property type

Question

the question is this: How I can I restrict my validation attribute to be used for only one type?, For example only DateTime.

Currently I do this control method "IsValid":

protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
    if (value == null || value.GetType() != typeof(DateTime))
    {
        return ValidationResult.Success;
    }
    ...
}

I would like this in the constructor, but I do not know how to detect the type of the attribute to which it applies, or an attribute such as:

[AttributeUsage(AttributeTargets.Property, ...)]
public class MyValidateDatesAttibute : ValidationAttribute, IClientValidatable
{
   ...
}

where it limits the use of my only attribute properties.

Thank you.