using System; using System.Collections.Generic; using System.Globalization; using System.Text; using System.Windows.Controls; namespace bindings { // public class FutureDateRule : ValidationRule { public override ValidationResult Validate(object value, CultureInfo cultureInfo) { // Test if date is valid if (DateTime.TryParse(value.ToString(), out DateTime date)) { // Date is not in the future, fail if (DateTime.Now > date) return new ValidationResult(false, "Please enter a date in the future."); } else { // Date is not a valid date, fail return new ValidationResult(false, "Value is not a valid date."); } // Date is valid and in the future, pass return ValidationResult.ValidResult; } } // }