protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
// Get values
var comparableValue = value as IComparable;
IComparable comparableOtherValue;
try {
comparableOtherValue = validationContext.GetPropertyValue<IComparable>(this.OtherPropertyName);
}
catch (ArgumentException aex) {
throw new InvalidOperationException("Other property not found", aex);
}
// Empty or noncomparable values are valid - let others validate that
if (comparableValue == null || comparableOtherValue == null) return ValidationResult.Success;
var compareResult = comparableValue.CompareTo(comparableOtherValue);
if (compareResult == 1 || (this.AllowEqual && compareResult == 0)) {
// This property is greater than other property or equal when permitted
return ValidationResult.Success;
}
else {
// This property is smaller or equal to the other property
if (string.IsNullOrWhiteSpace(this.OtherPropertyDisplayName)) {
this.OtherPropertyDisplayName = validationContext.GetPropertyDisplayName(this.OtherPropertyName);
}
return new ValidationResult(this.FormatErrorMessage(validationContext.DisplayName));
}
}