Question

如果出现问题，我想验证文本框。这个想法是，如果出现问题，那么下一个TextBox应该有一个警告图像。

<TextBox Text="{Binding Age, UpdateSourceTrigger=PropertyChanged}">
    <Validation.ErrorTemplate>
        <ControlTemplate>
            <StackPanel>
                <!-- Placeholder for the TextBox itself -->
                <AdornedElementPlaceholder x:Name="textBox"/>
                <image source="some-Image.png" width="20" Height="20" />
            </StackPanel>
        </ControlTemplate>
    </Validation.ErrorTemplate>
</TextBox>

但事情是图像没有显示，它只显示图标的边框。我正确使用AdornedElementPlaceholder吗？

Answer 1

经过测试的解决方案，可在发生错误时显示图像：

/**
 * Controller action
 */
function myAction() {
  if ($this->isAdmin()) {
    throw new \Exception('You need to be an admin');
  }

  $this->userService->create($_POST);
}

/**
 * Service containing actions related to users
 */
class UserService {

  /**
   * @var UserValidator
   */
  protected $validator;

  /**
   * @var RecordSaver
   */
  protected $recordSaver;

  /**
   * @param UserValidator $validator
   * @param RecordSaver $recordSaver
   */
  public function __construct(
    UserValidator $validator, 
    RecordSaver $recordSaver
  ) {
    $this->validator = $validator;
    $this->recordSaver = $recordSaver;
  }

  /**
   * @param $params
   * @return array
   */
  public function create($params) {
    $this->validator->validate($params);

    return $this->recordSaver->save($params);
  }
}

/**
 * Validation of new users / or updating existing
 */
class UserValidator {
  /**
   * @param array $params
   * @throws Exception
   */
  public function validate($params) {
    if (!isset($params['username'])) {
      throw new \Exception('Username must be set');
    }
  }
}

/**
 * Wrapper for database calls
 */
class RecordSaver {
  /**
   * @param array $params
   * @return array
   */
  public function save($params) {
    return create_record($params);
  }
}

以下是我用于此示例的验证规则：

<TextBox BorderThickness="0.8">
    <Validation.ErrorTemplate>
        <ControlTemplate>
            <StackPanel>
                <AdornedElementPlaceholder/>
                <Image Source="Image.jpg" Width="20" Height="20"/>
            </StackPanel>
        </ControlTemplate>
    </Validation.ErrorTemplate>
    <TextBox.Text>
        <Binding Path="ValidationTest" UpdateSourceTrigger="PropertyChanged" Mode="TwoWay" ValidatesOnDataErrors="True">
            <Binding.ValidationRules>
                <validation:IntegerValidationRule ValidationStep="CommittedValue" Min="1" Max="99999999"/>
            </Binding.ValidationRules>
        </Binding>
    </TextBox.Text>
</TextBox>

这是MSDN Docs的修改示例 有些说明：
您没有提供验证规则，因此我假设它按预期工作并生成有效的验证结果您的public class IntegerValidationRule : ValidationRule { private int _min = int.MinValue; private int _max = int.MaxValue; private string _fieldName = "Field"; private string _customMessage = String.Empty; public int Min { get { return _min; } set { _min = value; } } public int Max { get { return _max; } set { _max = value; } } public string FieldName { get { return _fieldName; } set { _fieldName = value; } } public string CustomMessage { get { return _customMessage; } set { _customMessage = value; } } public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo) { int num = 0; var val = (value as BindingExpression).DataItem; if (!int.TryParse(value.ToString(), out num)) return new ValidationResult(false, $"{FieldName} must contain an integer value."); if (num < Min || num > Max) { if (!String.IsNullOrEmpty(CustomMessage)) return new ValidationResult(false, CustomMessage); return new ValidationResult(false, $"{FieldName} must be between {Min} and {Max}."); } return new ValidationResult(true, null); } }属性的绑定不包括验证规则。

验证时向TextBox添加警告图标

1 个答案: