如何获取使用星形定义的WPF网格列来剪辑内容？

Question

我有一个使用星形比例的网格控件,例如

<Grid.ColumnDefinitions>
    <ColumnDefinition Width="50*" />
    <ColumnDefinition Width="100*" />
    <ColumnDefinition Width="50*" />
</Grid.ColumnDefinitions>

然而TextBlock,在网格中长时间溢出导致比例被打乱.例如

<TextBlock Text="Foo" Grid.Column="0" />
<TextBlock Text="Some long text here which overflows" Grid.Column="1" />
<TextBlock Text="Foo" Grid.Column="2" />

这导致中心列比另外两列多两倍.如何保持指定的比例？是否可以剪辑内容？

我已经设置TextTrimming="CharacterEllipsis"的TextBlocks,但没有运气.

编辑

至关重要的是,网格在里面DataTemplate,粘贴以下内容来观察行为,

<!-- FallbackValue is just a quick hack to get some rows to show at design-time -->
<ListBox ItemsSource="{Binding Foo, FallbackValue=1234}"
             HorizontalContentAlignment="Stretch">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="50*" />
                        <ColumnDefinition Width="100*" />
                        <ColumnDefinition Width="50*" />
                    </Grid.ColumnDefinitions>
                    <TextBlock Text="Foo" Grid.Column="0" />
                    <TextBlock Text="Some long text here which overflows" TextTrimming="CharacterEllipsis" Grid.Column="1" />
                    <TextBlock Text="Foo"  Grid.Column="2" />
                </Grid>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

这很重要的原因是我有另一个Grid作为兄弟姐妹,ListBox它显示了ListBox如下所示列的'标题' ,

<Grid>
    ... Headers and column definitions here
</Grid>

<ListBox ...>
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Grid>
                ... Matching column definitions here
            </Grid>
        </DateTemplate>
    </ListBox.ItemTemplate>
</ListBox>

所以列匹配很重要.

我试图将ColumnDefinitions内部绑定DataTemplate到外部Grid ColumnDefinitions但我无法轻易地获得对它的绑定引用.

Answer 1

这是WPF最烦人的问题之一.由于产生模板化网格的可用空间是无限的,因此实际内容将占用所需的空间.

最简单的方法是为Grid固定一定的宽度,但这只能解决没有调整大小的情况.

虽然你想要拉伸ListBox大小(宽度,在特定的),不幸的是我想除了自定义转换器之外没有任何更好的解决方案.

这是我的解决方案:

<Window.Resources>
    <local:MyConv x:Key="cv1" />
</Window.Resources>
<Grid>
    <ListBox 
        ItemsSource="{Binding Foo, FallbackValue=1234}"
        HorizontalContentAlignment="Stretch"
        >
        <ListBox.ItemTemplate>
            <DataTemplate>
                <Grid Width="{Binding Path=ActualWidth, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListBox}, Converter={StaticResource cv1}}">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="50*" />
                        <ColumnDefinition Width="100*" />
                        <ColumnDefinition Width="50*" />
                    </Grid.ColumnDefinitions>
                    <TextBlock Text="Foo" Grid.Column="0" />
                    <TextBlock Text="Some long text here which overflows" TextTrimming="CharacterEllipsis" Grid.Column="1" />
                    <TextBlock Text="Foo"  Grid.Column="2" />
                </Grid>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>

和转换器:

class MyConv : IValueConverter
{
    public object Convert(
        object value, 
        Type targetType, 
        object parameter, 
        System.Globalization.CultureInfo culture
        )
    {
        return (double)value - 30.0;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}