Question

我运行了WPF验证（将ValidationRules添加到绑定中）并且使用模板我可以创建漂亮的装饰器。那里有很多帖子。

但我找不到在窗口一角的固定位置（例如TextBlock）显示装饰控件之外的错误消息的方法，例如

我怎么能实现这个目标？我可以将所有验证错误消息绑定到DataContext（此处为ViewModel）吗？

更新：由于答案我得到了部分工作。验证消息现在显示在另一个标签中。由于所有带有验证规则的文本框都是通过代码动态创建的，因此以这种方式完成绑定：

Binding bindSite = new Binding();
bindSite.Source = this.validationErrorDisplayLabel;
BindingOperations.SetBinding(textBox, Validation.ValidationAdornerSiteProperty, bindSite);

但验证消息仅转发到执行此代码的最后一个文本框的adornersite。

我在这个小例子中重现了这个问题。

XAML：

<Grid>
    <TextBox 
        Validation.ValidationAdornerSite="{Binding ElementName=ErrorDisplay}"
        HorizontalAlignment="Left" Height="23" Margin="10,10,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120">
        <TextBox.Text>
            <Binding>
                <Binding.Path>Box1</Binding.Path>
                <Binding.ValidationRules>
                    <local:RuleA />
                </Binding.ValidationRules>
            </Binding>
        </TextBox.Text>
    </TextBox>
    <TextBox 
        Validation.ValidationAdornerSite="{Binding ElementName=ErrorDisplay}"
        HorizontalAlignment="Left" Height="23" Margin="10,38,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120">
        <TextBox.Text>
            <Binding>
                <Binding.Path>Box2</Binding.Path>
                <Binding.ValidationRules>
                    <local:RuleA />
                </Binding.ValidationRules>
            </Binding>
        </TextBox.Text>
    </TextBox>
    <TextBlock 
        x:Name="ErrorDisplay"
        Background="AntiqueWhite"
        Foreground="Red"
        Text="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=(Validation.ValidationAdornerSiteFor).(Validation.Errors)[0].ErrorContent}"
        HorizontalAlignment="Left" Margin="230,10,0,0" TextWrapping="Wrap" VerticalAlignment="Top" RenderTransformOrigin="2.218,-4.577" Width="177" Height="51"/>
</Grid>

当值等于字符串RuleA时，类"A"会产生验证错误。第二个文本框中的错误显示在TextBlock中，第一个文本框中的错误没有显示（而是使用默认模板并获得红色边框）。

两者如何运作？文本块不需要总结所有错误，但会显示第一个错误。

Answer 1

您可以将BindingGroup与Validation.ValidationAdornerSite和Validation.ValidationAdornerSiteFor属性结合使用。

This blog post向您展示了如何执行此操作的示例。

<StackPanel x:Name="FormRoot"
            Validation.ValidationAdornerSite="{Binding ElementName=ErrorDisplay}">
  <FrameworkElement.BindingGroup>
    <BindingGroup Name="FormBindingGroup" />
  </FrameworkElement.BindingGroup>

  <TextBox>
    <TextBox.Text>
      <Binding BindingGroupName="FormBindingGroup"
               UpdateSourceTrigger="LostFocus"
               Path="Box1">
        <Binding.ValidationRules>
          <l:RuleA />
        </Binding.ValidationRules>
      </Binding>
    </TextBox.Text>
  </TextBox>

<TextBox>
    <TextBox.Text>
      <Binding BindingGroupName="FormBindingGroup"
               UpdateSourceTrigger="LostFocus"
               Path="Box2">
        <Binding.ValidationRules>
          <l:RuleA />
        </Binding.ValidationRules>
      </Binding>
    </TextBox.Text>
  </TextBox>

  <ItemsControl x:Name="ErrorDisplay"
                Background="AntiqueWhite"
                Foreground="Red"
                ItemsSource="{Binding RelativeSource={RelativeSource Self},
                                      Path=(Validation.ValidationAdornerSiteFor).(Validation.Errors)}"
                DisplayMemberPath="ErrorContent" />
</StackPanel>

要在用户输入时提交值，请将UpdateSourceTrigger值更改为PropertyChanged。请注意，在此处使用ValidationAdornerSite并非绝对必要;您只需将ErrorDisplay绑定直接指向BindingGroup的所有者：

即可

ItemsSource="{Binding ElementName=FormRoot, Path=(Validation.Errors)}"

Answer 2

感谢http://www.scottlogic.com/blog/2008/11/28/using-bindinggroups-for-greater-control-over-input-validation.html我能够使用BindingGroup和没有ValidationAdornerSite来解决这个问题。

<Window x:Class="BindingAndValidation.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:BindingAndValidation"
        Title="Binding and Validation" Height="110" Width="425"
        DataContext="{Binding RelativeSource={RelativeSource Self}}"
        >
    <Grid x:Name="RootElement">
        <Grid.Resources>
            <Style TargetType="{x:Type TextBox}">
                <Style.Triggers>
                    <Trigger Property="Validation.HasError" Value="true">
                        <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}" />
                    </Trigger>
                </Style.Triggers>
            </Style>
        </Grid.Resources>
        <Grid.BindingGroup>
            <BindingGroup Name="LocalBindingGroup">
                <BindingGroup.ValidationRules>
                    <local:RuleGroup />
                </BindingGroup.ValidationRules>
            </BindingGroup>
        </Grid.BindingGroup>
        <TextBox 
            HorizontalAlignment="Left" Height="23" Margin="10,10,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120" LostFocus="TextBox_LostFocus">
            <TextBox.Text>
                <Binding>
                    <Binding.Path>Box1</Binding.Path>
                    <Binding.BindingGroupName>LocalBindingGroup</Binding.BindingGroupName>
                    <Binding.ValidationRules>
                        <local:RuleA />
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>
        <TextBox 
            HorizontalAlignment="Left" Height="23" Margin="10,38,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120">
            <TextBox.Text>
                <Binding>
                    <Binding.Path>Box2</Binding.Path>
                    <Binding.BindingGroupName>LocalBindingGroup</Binding.BindingGroupName>
                    <Binding.ValidationRules>
                        <local:RuleA />
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>
        <ItemsControl ItemsSource="{Binding Path=(Validation.Errors), ElementName=RootElement}" MinWidth="100" MinHeight="16" Margin="230,10,0,0" Background="AntiqueWhite" Foreground="Red">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Label Foreground="Red" Content="{Binding Path=ErrorContent}"/>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
        <Button Content="Button" HorizontalAlignment="Left" Margin="150,0,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click" />
    </Grid>
</Window>

只有在您致电CommitEdit时才会进行验证。如果您希望立即使用它，我可以使用LostFocus

    private void TextBox_LostFocus(object sender, RoutedEventArgs e)
    {
        this.RootElement.BindingGroup.CommitEdit();
    }

当然，对于一个更大的项目，附属财产可能有所帮助。

在固定位置显示WPF验证错误消息

2 个答案: