private void FormTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            var result = MyValidationRule?.Validate(this.Text, System.Globalization.CultureInfo.CurrentCulture);

            ValidationHasError     = !result.IsValid;
            ValidationErrorMessage = result.ErrorContent?.ToString();
        }
        public bool ValidationCheckError()
        {
            var result = MyValidationRule?.Validate(this.Text, System.Globalization.CultureInfo.CurrentCulture);

            ValidationHasError     = !result.IsValid;
            ValidationErrorMessage = result.ErrorContent?.ToString();
            return(ValidationHasError);
        }