namespace System.Configuration { public class PositiveTimeSpanValidator : ConfigurationValidatorBase { public override bool CanValidate(Type type) { return type == typeof(TimeSpan); } public override void Validate(object value) { if (value == null) throw new ArgumentNullException("value"); if ((TimeSpan)value <= TimeSpan.Zero) throw new ArgumentException(System.SR.Validator_timespan_value_must_be_positive); } } }