using System; using System.Globalization; using System.Windows.Controls; namespace MaterialDesignDemo.Domain { public class SimpleDateValidationRule : ValidationRule { public override ValidationResult Validate(object value, CultureInfo cultureInfo) { DateTime time; return DateTime.TryParse((value ?? "").ToString(), CultureInfo.CurrentCulture, DateTimeStyles.AssumeLocal | DateTimeStyles.AllowWhiteSpaces, out time) ? ValidationResult.ValidResult : new ValidationResult(false, "Invalid date"); } } }