ValidationRule.ValidatesOnTargetUpdated 属性

定义

获取或设置一个值,该值指示当 Binding 的目标更新时是否运行验证规则。

public:
 property bool ValidatesOnTargetUpdated { bool get(); void set(bool value); };
public bool ValidatesOnTargetUpdated { get; set; }
member this.ValidatesOnTargetUpdated : bool with get, set
Public Property ValidatesOnTargetUpdated As Boolean

属性值

如果在 Binding 的目标更新时运行验证规则,则为 true;否则为 false

示例

以下示例检查 是否 TextBox 为空。 、 已设置为 ,因此,在应用程序启动时,如果 为空, 将ValidationRule运行并显示一条消息TextBoxtrueValidatesOnTargetUpdatedValueIsNotNullValidationRule

<TextBox Width="150"
         Validation.Error="ItemError">
  <TextBox.Text>
    <Binding Source="{StaticResource myObject}"
             Path="PropertyB"
             UpdateSourceTrigger="PropertyChanged"
             NotifyOnValidationError="True">
      <Binding.ValidationRules>
        <src:ValueIsNotNull ValidatesOnTargetUpdated="True" />
      </Binding.ValidationRules>
    </Binding>
  </TextBox.Text>
</TextBox>

以下示例显示了 ValidationRule 在上一个示例中使用的 以及 事件的事件处理程序 Error

public class ValueIsNotNull : ValidationRule
{
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
    {
        string str = value as string;

        if (!string.IsNullOrEmpty(str))
        {
            return ValidationResult.ValidResult;
        }
        else
        {
            return new ValidationResult(false, "Value must not be null");
        }
    }
}
Public Class ValueIsNotNull
    Inherits ValidationRule
    Public Overrides Function Validate(ByVal value As Object, ByVal cultureInfo As System.Globalization.CultureInfo) As ValidationResult
        Dim str As String = TryCast(value, String)

        If Not String.IsNullOrEmpty(str) Then
            Return ValidationResult.ValidResult
        Else
            Return New ValidationResult(False, "Value must not be null")
        End If
    End Function
End Class

适用于