Question

我正在尝试生成FlowDocument，并希望某些文本运行在包含特定字符串时突出显示。我正在使用BindableRun类来确保我可以更新Run文本值（虽然我只在构造时设置它们，所以Run的vanilla实例应该没问题。）

基本上，我想这样做：

 <FlowDocument Name="FlowDoc" FontFamily="{x:Static SystemFonts.CaptionFontFamily}" 
                  Background="{x:Static SystemColors.ControlBrush}" 
                  FontSize="{x:Static SystemFonts.SmallCaptionFontSize}"
                  TextAlignment="Left">
      <FlowDocument.Resources>
        <Style TargetType="{x:Type local:BindableRun}">
          <!-- 1. Style all BindableRuns with a pink background by default -->
          <Setter Property="Background" Value="HotPink"/>

          <Style.Triggers>

            <!-- 2. Style BindableRuns where Text=Hello to have a green background-->
            <DataTrigger Binding="{Binding BoundText}" Value="Hello">
              <Setter Property="Background" Value="GreenYellow"/>
            </DataTrigger>
            <!-- 3. Fire a Datatrigger with parameterised converter to change 
                  text to Orange if the text contains 'StackOverflow'-->
            <DataTrigger Binding="{Binding BoundText, 
                           Converter={StaticResource ContainsBoolConverter},
                           ConverterParameter=StackOverflow}" Value="False">
              <Setter Property="Foreground" Value="Orange"/>
            </DataTrigger>
          </Style.Triggers>
        </Style>
      </FlowDocument.Resources>
    </FlowDocument>

现在，当我尝试使用上面的Xaml时：

•改变BindableRun对象（即＃1）背景的样式运行正常 - 所以FlowDocument的内容是我所期待的

•针对BindableRun对象的BountText属性的DataTriggers不起作用。

•转换器甚至没有被调用（我在它上面放了一个断点）所以看起来绑定/ datatrigger就是没有触发。

之前有人做过这样的事吗？如果是这样，你有没有设法让它工作？在SO等上没有那么多的FlowDocument示例，所以我没有设法找到其他任何尝试（成功或不成功）在Run的Text属性上使用DataTriggers的人。

作为参考，这里是我正在使用的Contains转换器（虽然它根本不会触发，所以无论它是否正确都无关紧;）。）。

public class ContainsTextConverter : IValueConverter
{
    public object Convert( object value, Type t, object parameter, CultureInfo culture )
    {
        String input = value.ToString();
        string param = parameter.ToString();

        return input.IndexOf( param, StringComparison.OrdinalIgnoreCase ) != -1;
    }

    public object ConvertBack( object value, Type t, object parameter, CultureInfo culture )
    {
        // Don't care about this
        throw new NotSupportedException();
    }
};

Answer 1

将RelativeSource={RelativeSource Self}添加到两个DataTrigger绑定中。默认情况下，绑定会查找控件DataContext的属性。要使其查找控件的属性，您需要RelativeSource参数。

    <!-- 2. Style BindableRuns where Text=Hello to have a green background-->
    <DataTrigger Binding="{Binding BoundText, RelativeSource={RelativeSource Self}}" Value="Hello">
        <Setter Property="Background" Value="GreenYellow"/>
    </DataTrigger>

    <!-- 3. Fire a Datatrigger with parameterised converter to change text to Orange if the text contains 'StackOverflow'-->
    <DataTrigger Binding="{Binding BoundText, RelativeSource={RelativeSource Self},
            Converter={StaticResource ContainsTextConverter},
            ConverterParameter=StackOverflow}" Value="True">
        <Setter Property="Foreground" Value="Orange"/>
    </DataTrigger>

这将解决“Hello”没有绿色背景的问题。

现在，您的转换器示例还有一些其他问题：

转换器的名称为ContainsTextConverter，但您引用了{StaticResource ContainsBoolConverter}。
当您说希望文本包含参数时，您为条件指定Value="False"。
您需要确保转换器中的值不是null。它会被调用每个BindableRun，但如果在设置DataContext之前加载XAML，则可以使用null调用它。

public object Convert( object value, Type t, object parameter, CultureInfo culture )
{
    if( value != null )
    {
        return (value as String).IndexOf( parameter as String, StringComparison.OrdinalIgnoreCase ) != -1;
    }
    else return false;
}

进行这些更改后，您会看到DataTrigger都正常工作。

Answer 2

要获得一个单词的检查，您需要编写一个这样的触发器：

<Trigger Property="BindableText" Value="text">
    <Setter Property="Background" Value="GreenYellow" />
</Trigger>

现在，如果字符串是text，则触发我们的触发器。

关于Converter，我尝试了不同的选项，但传递给Converter的值始终为Null。然后我决定走另一条路。之后，您为属性BindableText创建了一个类，因此我决定再添加两个类：

一个用于验证传递给转换器的字符串的属性（StackOverflow字符串）。
Brush类型的一个属性，用于设置颜色。

所以，我的完整例子：

XAML

<Grid>
    <FlowDocumentScrollViewer>
        <FlowDocument>
            <FlowDocument.Resources>
                <Style TargetType="{x:Type local:BindableExtender}">
                    <Style.Triggers>
                        <Trigger Property="BindableText" Value="text">
                            <Setter Property="Background" Value="GreenYellow"/>
                        </Trigger>                                                        
                    </Style.Triggers>
                </Style>
            </FlowDocument.Resources>

            <Paragraph>
                Binding string:

                <local:BindableExtender BindableText="{Binding ElementName=MyTextBox, Path=Text}"
                                        CompareText="StackOverflow"
                                        ForegroundBrush="OrangeRed" />
            </Paragraph>

            <BlockUIContainer>
                <TextBox Name="MyTextBox" Text="text"/>
            </BlockUIContainer>
        </FlowDocument>
    </FlowDocumentScrollViewer>
</Grid>

Code behind

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
}

public class BindableExtender : Run
{
    #region BindableText declaration

    public String BindableText
    {
        get 
        { 
            return (string)GetValue(BindableTextProperty); 
        }

        set 
        { 
            SetValue(BindableTextProperty, value); 
        }
    }

    public static readonly DependencyProperty BindableTextProperty =
        DependencyProperty.Register("BindableText",
            typeof(string),
            typeof(BindableExtender),
            new UIPropertyMetadata(null, BindableTextProperty_PropertyChanged));

    private static void BindableTextProperty_PropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
    {
        BindableExtender MyRun = dependencyObject as BindableExtender;

        if (dependencyObject is BindableExtender)
        {
            MyRun.Text = (string)e.NewValue;
            string bind = (string)e.NewValue;

            // Check the two strings
            if (bind.IndexOf(MyRun.CompareText, StringComparison.OrdinalIgnoreCase) != -1)
            {
                MyRun.Foreground = MyRun.ForegroundBrush;
            }
            else
            {
                MyRun.Foreground = Brushes.Black;
            }
        }
    }

    #endregion BindableText declaration

    #region CompareText declaration

    public String CompareText
    {
        get 
        { 
            return (string)GetValue(CompareProperty); 
        }

        set 
        {
            SetValue(CompareProperty, value); 
        }
    }

    public static readonly DependencyProperty CompareProperty =
        DependencyProperty.Register("CompareText",
            typeof(string),
            typeof(BindableExtender),
            new UIPropertyMetadata(null, CompareProperty_PropertyChanged));

    private static void CompareProperty_PropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
    {
        BindableExtender MyRun = dependencyObject as BindableExtender;
        string CompareString = e.NewValue as string;

        // Save the value in CompareText property
        MyRun.CompareText = CompareString;
    }

    #endregion

    #region ForegroundBrush declaration

    public Brush ForegroundBrush
    {
        get
        {
            return (Brush)GetValue(ForegroundBrushProperty);
        }

        set
        {
            SetValue(ForegroundBrushProperty, value);
        }
    }

    public static readonly DependencyProperty ForegroundBrushProperty =
        DependencyProperty.Register("ForegroundBrush",
            typeof(Brush),
            typeof(BindableExtender),
            new UIPropertyMetadata(null, ForegroundBrushProperty_PropertyChanged));

    private static void ForegroundBrushProperty_PropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
    {
        BindableExtender MyRun = dependencyObject as BindableExtender;
        Brush NewForegroundBrush = e.NewValue as Brush;

        // Save the value in ForegroundBrush property
        MyRun.ForegroundBrush = NewForegroundBrush;
    }

    #endregion
}

Output #1

enter image description here

Output #2

enter image description here

颜色编码文本在FlowDocument中运行

2 个答案: