未顯示Passwordbox Validation.ErrorTemplate

我試圖顯示PasswordBox的Validation.ErrorTemplate。但是，它沒有顯示。在同一表單上，我有一個用戶名TextBox，並且ErrorTemplate顯示正確。未顯示Passwordbox Validation.ErrorTemplate

的XAML在datatempalte的PasswordBox：

<PasswordBox Grid.Row="3" DataContext="{Binding Path=DataContext, RelativeSource={RelativeSource AncestorType=ContentControl}}">      
    <PasswordBox.Style> 
    <Style> 
     <Setter Property="Validation.ErrorTemplate"> 
     <Setter.Value> 
      <ControlTemplate> 
      <DockPanel LastChildFill="True"> 
       <TextBlock DockPanel.Dock="Right" Foreground="Red" FontSize="14" FontWeight="Bold">*</TextBlock> 
       <Border BorderBrush="Red" BorderThickness="1"> 
       <AdornedElementPlaceholder/> 
       </Border> 
      </DockPanel> 
      </ControlTemplate> 
     </Setter.Value> 
     </Setter> 
    </Style> 
    </PasswordBox.Style> 

    <i:Interaction.Behaviors> 
    <behavior:PasswordBoxBehaviorBinding SPassword="{Binding Path=Password, ValidatesOnNotifyDataErrors=True}" /> 
    </i:Interaction.Behaviors> 
</PasswordBox>

下面是附加屬性我使用。

public class PasswordBoxBehaviorBinding : Behavior<PasswordBox> 
{ 
    public SecureString SPassword 
    { 
     get { return (SecureString)GetValue(PasswordProperty); } 
     set { SetValue(PasswordProperty, value); } 
    } 

    public static readonly DependencyProperty PasswordProperty 
     = DependencyProperty.Register(
      "SPassword", 
      typeof(SecureString), 
      typeof(PasswordBoxBehaviorBinding), 
      new PropertyMetadata(null)); 

    protected override void OnAttached() 
    { 
     AssociatedObject.PasswordChanged += AssociatedObject_PasswordChanged;      
     base.OnAttached(); 
    } 

    protected override void OnDetaching() 
    { 
     AssociatedObject.PasswordChanged += AssociatedObject_PasswordChanged; 
     base.OnDetaching(); 
    } 

    private void AssociatedObject_PasswordChanged(object sender, RoutedEventArgs e) 
    {    
     var binding = BindingOperations.GetBindingExpression(this, PasswordProperty); 
     if (binding != null) 
     { 
      if (binding.ResolvedSource != null) 
      { 
       PropertyInfo property = binding.ResolvedSource.GetType() 
        .GetProperty(binding.ParentBinding.Path.Path); 

       if (property != null) 
       { 
        property.SetValue(binding.ResolvedSource, AssociatedObject.SecurePassword); 
       } 
      } 
     } 
    } 
}

我在基本viewmodel中實現了INotifyDataError接口。

public class ViewModelBase : BindableBase, INotifyDataErrorInfo 
{ 
    private IDictionary<string, List<string>> errors 
     = new Dictionary<string, List<string>>(); 

    public bool HasErrors 
    { 
     get 
     { 
      return this.errors.Count > 0; 
     } 
    } 

    public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged; 

    public IEnumerable GetErrors(string propertyName) 
    { 
     if (this.errors.ContainsKey(propertyName)) 
     { 
      return this.errors[propertyName]; 
     } 
     return null; 
    } 

    public void AddError(string propertyName, string error) 
    { 
     this.errors[propertyName] = new List<string> { error };   
     this.RaiseErrorsChanged(propertyName); 
    } 

    public void RemoveError(string propertyName) 
    { 
     if (this.errors.ContainsKey(propertyName)) 
     { 
      this.errors.Remove(propertyName); 
     } 
     this.RaiseErrorsChanged(propertyName); 
    } 

    private void RaiseErrorsChanged(string propertyName) 
    { 
     if (this.ErrorsChanged != null) 
     { 
      this.ErrorsChanged(this, new DataErrorsChangedEventArgs(propertyName)); 
     } 
    } 
}

來源

2016-10-19 Swapnil Shah

試試 – Nathan

@Nathan，感謝您的建議。但是這並沒有解決這個問題。 –

您嘗試了哪些解決方法以及結果如何？你有沒有嘗試在InitializeComponent之後的代碼中設置DataContext？您是否嘗試過構建一個簡單的bootleg項目來顯示自定義驗證錯誤並逐步將其修改爲您當前的代碼？您是否嘗試過在Validation.HasError中添加觸發器以查看是否出現默認驗證錯誤？ – Nathan

的問題是，該錯誤是在承載在驗證錯誤發生數據綁定屬性DependencyObject上升。你的情況<behavior:PasswordBoxBehaviorBinding SPassword="{Binding Path=Password, ValidatesOnNotifyDataErrors=True}" />的意思是，你可以讀取你的行爲內的錯誤。

在這一點上，我也想建議你對SPassword的綁定做的奇怪的黑客攻擊。只需設定值正常：

private void AssociatedObject_PasswordChanged(object sender, System.Windows.RoutedEventArgs e) 
{ 
    SPassword = AssociatedObject.SecurePassword; 
    // use debugger to verify, that the validation errors exist. Otherwise, no need for the following line of code 
    var behaviorErrors = Validation.GetErrors(this); 
}

不幸的是，我還沒有發現，如何促進從附加的行爲，以控制主機的Validation.Errors以一種優雅的方式。因此，基本上，您的選擇將以某種方式將錯誤從行爲鏈接到密碼箱，或者爲您的屬性創建額外綁定，因爲此綁定將使用相同的驗證機制，因此在PasswordBox上設置Validation.Errors。爲了錯誤傳播的目的，我決定將視圖模型Password綁定到PasswordBox.Tag。

<PasswordBox Width="200" Height="100" Tag="{Binding Password,ValidatesOnNotifyDataErrors=True,Mode=OneWay}"> 
    <i:Interaction.Behaviors> 
     <behavior:PasswordBoxBehaviorBinding SPassword="{Binding Password}"/> 
    </i:Interaction.Behaviors> 
</PasswordBox>

注意，我刪除從行爲綁定綁定錯誤驗證，因爲它不是反正有用，我增加了綁定錯誤驗證爲Tag結合。

一兩件事：我改變了SPassword屬性默認綁定雙向：

public static readonly DependencyProperty PasswordProperty = DependencyProperty.Register(
    "SPassword", 
    typeof(SecureString), 
    typeof(PasswordBoxBehaviorBinding), 
    new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));

否則，請務必設置適當的結合模式。

來源

2016-10-19 22:47:39 grek40

未顯示Passwordbox Validation.ErrorTemplate

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