Wpf 从左开始修剪文本_Wpf_Silverlight_Xaml_Texttrimming

Wpf 从左开始修剪文本

wpf silverlight xaml

Wpf 从左开始修剪文本,wpf,silverlight,xaml,texttrimming,Wpf,Silverlight,Xaml,Texttrimming,有没有办法将TextBlock上的文本修剪指定为从左侧开始我已经成功完成了三个场景中的两个（第三个是我需要的场景）：定期修剪 <TextBlock VerticalAlignment="Center" Width="80" TextTrimming="WordEllipsis" Text="A very long text that requires trimming" /> // Result: "A very long te..."

有没有办法将

TextBlock

上的文本修剪指定为从左侧开始

我已经成功完成了三个场景中的两个（第三个是我需要的场景）：

定期修剪

<TextBlock 
    VerticalAlignment="Center" 
    Width="80" 
    TextTrimming="WordEllipsis"
    Text="A very long text that requires trimming" />

// Result: "A very long te..."

有人知道这是否可能吗？谢谢

你不能开箱即用，但我可以想到两件事：

1）为TextBlock创建一个名为LeftTrimmingText的附加属性。然后，您将设置此属性而不是文本属性。例如

  <TextBlock my:TextBlockHelper.LeftTrimmingText="A very long text that requires trimming." />

附加属性将计算实际可以显示的字符数，然后相应地设置TextBlock的Text属性

2）创建自己的类来包装一个TextBlock，并添加自己的属性来处理所需的逻辑

我认为第一个选项更容易。

我不知道这是否是打字错误，但你错过了“期望结果”末尾的

句号。我想你不会想要的。因为您知道应该显示多少个字符，所以只需获取整个字符串的子字符串并显示它即可。比如说,
string origText = "A very long text that requires trimming.";

//15 because the first three characters are replaced
const int MAXCHARACTERS = 15;

//MAXCHARACTERS - 1 because you don't want the full stop
string sub = origText.SubString(origText.Length-MAXCHARACTERS, MAXCHARACTERS-1);

string finalString = "..." + sub;
textBlock.Text = finalString;

如果您不知道在advanced中需要多少字符，则可以执行计算来确定它。在您的示例中，宽度为80
会产生17
个字符，如果宽度发生变化，您可以使用该比率
 如果不关心省略号，只想在文本被截断时看到文本的结尾而不是开头，可以将文本块包装到另一个容器中，并将其水平对齐设置为右侧。这将切断它就像你想要的，但没有省略
<Grid>
    <TextBlock Text="Really long text to cutoff." HorizontalAlignment="Right"/>
</Grid>

这种风格就可以了。诀窍是重新定义标签的控件模板。然后将内容放入剪裁画布中，并与画布右侧对齐。内容的最小宽度是画布的宽度，因此，如果有足够的空间，则内容文本将左对齐，剪裁时将右对齐
如果内容的宽度大于画布，则会触发省略号启用
<Style x:Key="LeftEllipsesLabelStyle"
       TargetType="{x:Type Label}">
    <Setter Property="Foreground"
            Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
    <Setter Property="Background"
            Value="Transparent" />
    <Setter Property="Padding"
            Value="5" />
    <Setter Property="HorizontalContentAlignment"
            Value="Left" />
    <Setter Property="VerticalContentAlignment"
            Value="Top" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Label}">
                <Grid >
                    <Grid.Resources>
                        <LinearGradientBrush x:Key="HeaderBackgroundOpacityMask" StartPoint="0,0" EndPoint="1,0">
                            <GradientStop Color="Black"  Offset="0"/>
                            <GradientStop Color="Black" Offset="0.5"/>
                            <GradientStop Color="Transparent" Offset="1"/>
                        </LinearGradientBrush>
                    </Grid.Resources>

                    <Canvas x:Name="Canvas" 
                            ClipToBounds="True" 
                            DockPanel.Dock="Top"  
                            Height="{Binding ElementName=Content, Path=ActualHeight}">

                        <Border 
                            BorderBrush="{TemplateBinding BorderBrush}"
                            Canvas.Right="0"
                            Canvas.ZIndex="0"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Background="{TemplateBinding Background}"
                            Padding="{TemplateBinding Padding}"
                            MinWidth="{Binding ElementName=Canvas, Path=ActualWidth}"
                            SnapsToDevicePixels="true"
                            x:Name="Content"
                        >
                            <ContentPresenter
                                HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                Content="{Binding RelativeSource={RelativeSource AncestorType=Label}, Path=Content}"
                                RecognizesAccessKey="True"
                                SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
                                VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                            >
                                <ContentPresenter.Resources>
                                    <Style TargetType="TextBlock">
                                        <Setter Property="FontSize" Value="{Binding FontSize, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                        <Setter Property="FontWeight" Value="{Binding FontWeight, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                        <Setter Property="FontStyle" Value="{Binding FontStyle, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                        <Setter Property="FontFamily" Value="{Binding FontFamily, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                    </Style>
                                </ContentPresenter.Resources>

                            </ContentPresenter>
                        </Border>
                        <Label 
                            x:Name="Ellipses" 
                            Canvas.Left="0" 
                            Canvas.ZIndex="10"
                            FontWeight="{TemplateBinding FontWeight}"
                            FontSize="{TemplateBinding FontSize}"
                            FontFamily="{TemplateBinding FontFamily}"
                            FontStyle="{TemplateBinding FontStyle}"
                            VerticalContentAlignment="Center" 
                            OpacityMask="{StaticResource HeaderBackgroundOpacityMask}" 
                            Background="{TemplateBinding Background}"
                            Foreground="RoyalBlue"
                            Height="{Binding ElementName=Content, Path=ActualHeight}" 
                            Content="...&#160;&#160;&#160;">
                            <Label.Resources>
                                <Style TargetType="Label">
                                    <Style.Triggers>
                                        <DataTrigger Value="true">
                                            <DataTrigger.Binding>
                                                <MultiBinding Converter="{StaticResource GteConverter}">
                                                    <Binding ElementName="Canvas" Path="ActualWidth"/>
                                                    <Binding ElementName="Content" Path="ActualWidth"/>
                                                </MultiBinding>
                                            </DataTrigger.Binding>
                                            <Setter Property="Visibility" Value="Hidden"/>
                                        </DataTrigger>
                                    </Style.Triggers>
                                </Style>
                            </Label.Resources>

                        </Label>
                    </Canvas>

                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsEnabled"
                             Value="false">
                        <Setter Property="Foreground"
                                Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

它在这里工作

不幸的是，第一个选择并不容易。Silverlight不公开文本呈现/度量API。您所能做的最好的事情就是检测何时发生修剪。请参阅这篇博文：ColinE:MeasurementAPI就是TextBlock本身。基本上，您可以在代码中创建一个新的临时文本块，并不断添加字符，直到实际宽度大于您想要的。temp TextBlock不需要渲染，甚至不需要在视觉树中渲染。谢谢，@RobSiklos和ColinEDon不要忘记-字符宽度取决于字体是的，我假设OP事先知道字体。如果不是，则OP可以使用此方法根据字体确定文本宽度：“在您的示例中，80个字符的宽度将产生17个字符，如果宽度发生变化，您可以使用该比率。”-每个字符可以（并且通常有）其各自的宽度。使用一个示例字符串的比率不会产生任何精确的结果。我认为您需要TextTrimming=“CharacterEllipsis”而不是WordEllipsis。出于某种原因，标签的不透明掩码对我来说无法正常工作，但我通过使用Background属性实现了我想要的效果-整洁的解决方案，谢谢！看起来是最干净的解决方案。虽然代码对我不起作用，但它根本不显示任何文本。你有关于如何使用它的示例吗？我是WPF和XAML的新手。我收到一个关于未定义命名空间前缀“c”以及未找到类型“c:GteConverter”的错误。我想我不是没有把所有的东西都放在正确的位置/文件里，就是缺少了一些东西。嗨，克里斯。我已经一年多没有使用XAML了，现在它对我来说又开始像黑魔法了。但是，上面的代码假定您知道如何处理XAML名称空间。如果不是的话，阅读可能会有所帮助。如果你不能以尽可能完整的信息开始另一个问题，那么最新的人可能会提供帮助。啊，无论如何，谢谢你的原始帖子。我想我会弄明白的。VisualStudio如何显示错误，而这些错误在实际编译代码时可能会消失，这让我感到厌烦。
<Grid>
    <TextBlock Text="Really long text to cutoff." HorizontalAlignment="Right"/>
</Grid>

<Style x:Key="LeftEllipsesLabelStyle"
       TargetType="{x:Type Label}">
    <Setter Property="Foreground"
            Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
    <Setter Property="Background"
            Value="Transparent" />
    <Setter Property="Padding"
            Value="5" />
    <Setter Property="HorizontalContentAlignment"
            Value="Left" />
    <Setter Property="VerticalContentAlignment"
            Value="Top" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Label}">
                <Grid >
                    <Grid.Resources>
                        <LinearGradientBrush x:Key="HeaderBackgroundOpacityMask" StartPoint="0,0" EndPoint="1,0">
                            <GradientStop Color="Black"  Offset="0"/>
                            <GradientStop Color="Black" Offset="0.5"/>
                            <GradientStop Color="Transparent" Offset="1"/>
                        </LinearGradientBrush>
                    </Grid.Resources>

                    <Canvas x:Name="Canvas" 
                            ClipToBounds="True" 
                            DockPanel.Dock="Top"  
                            Height="{Binding ElementName=Content, Path=ActualHeight}">

                        <Border 
                            BorderBrush="{TemplateBinding BorderBrush}"
                            Canvas.Right="0"
                            Canvas.ZIndex="0"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Background="{TemplateBinding Background}"
                            Padding="{TemplateBinding Padding}"
                            MinWidth="{Binding ElementName=Canvas, Path=ActualWidth}"
                            SnapsToDevicePixels="true"
                            x:Name="Content"
                        >
                            <ContentPresenter
                                HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                Content="{Binding RelativeSource={RelativeSource AncestorType=Label}, Path=Content}"
                                RecognizesAccessKey="True"
                                SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
                                VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                            >
                                <ContentPresenter.Resources>
                                    <Style TargetType="TextBlock">
                                        <Setter Property="FontSize" Value="{Binding FontSize, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                        <Setter Property="FontWeight" Value="{Binding FontWeight, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                        <Setter Property="FontStyle" Value="{Binding FontStyle, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                        <Setter Property="FontFamily" Value="{Binding FontFamily, RelativeSource={RelativeSource AncestorType={x:Type Label}}}"/> 
                                    </Style>
                                </ContentPresenter.Resources>

                            </ContentPresenter>
                        </Border>
                        <Label 
                            x:Name="Ellipses" 
                            Canvas.Left="0" 
                            Canvas.ZIndex="10"
                            FontWeight="{TemplateBinding FontWeight}"
                            FontSize="{TemplateBinding FontSize}"
                            FontFamily="{TemplateBinding FontFamily}"
                            FontStyle="{TemplateBinding FontStyle}"
                            VerticalContentAlignment="Center" 
                            OpacityMask="{StaticResource HeaderBackgroundOpacityMask}" 
                            Background="{TemplateBinding Background}"
                            Foreground="RoyalBlue"
                            Height="{Binding ElementName=Content, Path=ActualHeight}" 
                            Content="...&#160;&#160;&#160;">
                            <Label.Resources>
                                <Style TargetType="Label">
                                    <Style.Triggers>
                                        <DataTrigger Value="true">
                                            <DataTrigger.Binding>
                                                <MultiBinding Converter="{StaticResource GteConverter}">
                                                    <Binding ElementName="Canvas" Path="ActualWidth"/>
                                                    <Binding ElementName="Content" Path="ActualWidth"/>
                                                </MultiBinding>
                                            </DataTrigger.Binding>
                                            <Setter Property="Visibility" Value="Hidden"/>
                                        </DataTrigger>
                                    </Style.Triggers>
                                </Style>
                            </Label.Resources>

                        </Label>
                    </Canvas>

                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsEnabled"
                             Value="false">
                        <Setter Property="Foreground"
                                Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<c:GteConverter x:Key="GteConverter"/>

public class RelationalValueConverter : IMultiValueConverter
{
    public enum RelationsEnum
    {
        Gt,Lt,Gte,Lte,Eq,Neq
    }

    public RelationsEnum Relations { get; protected set; }

    public RelationalValueConverter(RelationsEnum relations)
    {
        Relations = relations;
    }

    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        if(values.Length!=2)
            throw new ArgumentException(@"Must have two parameters", "values");

        var v0 = values[0] as IComparable;
        var v1 = values[1] as IComparable;

        if(v0==null || v1==null)
            throw new ArgumentException(@"Must arguments must be IComparible", "values");

        var r = v0.CompareTo(v1);

        switch (Relations)
        {
            case RelationsEnum.Gt:
                return r > 0;
                break;
            case RelationsEnum.Lt:
                return r < 0;
                break;
            case RelationsEnum.Gte:
                return r >= 0;
                break;
            case RelationsEnum.Lte:
                return r <= 0;
                break;
            case RelationsEnum.Eq:
                return r == 0;
                break;
            case RelationsEnum.Neq:
                return r != 0;
                break;
            default:
                throw new ArgumentOutOfRangeException();
        }
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

public class GtConverter : RelationalValueConverter
{
    public GtConverter() : base(RelationsEnum.Gt) { }
}
public class GteConverter : RelationalValueConverter
{
    public GteConverter() : base(RelationsEnum.Gte) { }
}
public class LtConverter : RelationalValueConverter
{
    public LtConverter() : base(RelationsEnum.Lt) { }
}
public class LteConverter : RelationalValueConverter
{
    public LteConverter() : base(RelationsEnum.Lte) { }
}
public class EqConverter : RelationalValueConverter
{
    public EqConverter() : base(RelationsEnum.Eq) { }
}
public class NeqConverter : RelationalValueConverter
{
    public NeqConverter() : base(RelationsEnum.Neq) { }
}