[WPF] TextBlock的MaxHeight，长度表达式如何写，让其最多显示两行

[lgg06]

现在想让一TextBlock 最多显示两行（在Xaml中设置）， 不知其MaxHeight的表达式应该如果写， 也不知道哪里有相关的资料可参考

大侠帮帮忙，谢谢！

[lgg06]

自己顶

[zhouyongh]

[code=XAML]
<TextBox TextWrapping="Wrap" MaxLines="2" AcceptsReturn="True"/>
[/code]

Hope helps

[lgg06]

不好意思， 是TextBlock， 这个好像没有MaxLines 属性

Thanks all the same!

[lgg06]

自己再顶

[zhouyongh]

说实话，这么搞没啥意思。如果要限制行数，一行就够了，或者加个文字滚动，有时候也应该劝劝客户...

给你写了个TextBlockAttacher，可以只在XAML中设置。

public class TextBlockAttacher
{
    private const double FontSizeConstant = (double)4 / 3;  // 1/3 = lines spacing

    public static readonly DependencyProperty LimitedLineNumberProperty = DependencyProperty.RegisterAttached
        ("LimitedLineNumber",
         typeof(int),
         typeof(TextBlockAttacher),
         new FrameworkPropertyMetadata(new PropertyChangedCallback(LimitedLineNumberChanged)));

    public static void SetLimitedLineNumber(DependencyObject target, int value)
    {
        target.SetValue(TextBlockAttacher.LimitedLineNumberProperty, value);
    }

    private static void LimitedLineNumberChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
    {
        TextBlock txtBlock = target as TextBlock;

        if (txtBlock != null)
        {
            if (((int)e.NewValue != 0) && ((int)e.OldValue == 0))
            {
                txtBlock.Loaded += txtBlock_Loaded;
            }
            else if (((int)e.NewValue == 0) && ((int)e.OldValue != 0))
            {
                txtBlock.Loaded -= txtBlock_Loaded;
            }
        }
    }

    private static void txtBlock_Loaded(object sender, RoutedEventArgs e)
    {
        TextBlock txtBlock = sender as TextBlock;
        if (txtBlock != null)
        {
            int lineNumber = (int)txtBlock.GetValue(TextBlockAttacher.LimitedLineNumberProperty);
            double fontSize = txtBlock.FontSize * FontSizeConstant;
            txtBlock.MaxHeight = lineNumber * fontSize;
        }
    }

}

use like this:
[code=XAML]
<TextBlock src:TextBlockAttacher.LimitedLineNumber="2" FontSize="50" TextWrapping="Wrap" Text="Yohan Zhou 12122dasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasdasda" >
</TextBlock>
[/code]

Hope this helps

[lgg06]

万分感谢！

打工的没办法，PD怎么说就得怎样， QA也只是对着SPEC报Bug， 呵呵

[weng3998]

没有那么复杂 最高 是字的两倍多点 就行了
<TextBlock Margin="2,5" TextWrapping="Wrap" Text="Oracle server name:" HorizontalAlignment="Right" VerticalAlignment="Center" FontSize="13.333" MaxHeight="38" />