WPF ScrollViewer 在 ScrollBar 可见时显示边框

Question

我想为我的 ScrollViewer 添加边框。仅当 ScrollViewer 的 ScrollBar 可见时才应显示边框（VerticalScrollBarVisibility 设置为“Auto”）

谢谢！

Answer 1

您可以使用样式和触发器来执行此操作，如下所示：

<Border BorderBrush="Black">
    <Border.Style>
        <Style>
            <Setter Property="Border.Visibility" Value="Visible" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=theScrollViewer, Path=ComputedVerticalScrollBarVisibility}" Value="Collapsed">
                    <Setter Property="Border.Visibility" Value="Collapsed" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Border.Style>
    <ScrollViewer Name="theScrollViewer">
    </ScrollViewer>
</Border>

Answer 2

使用Binding 和Converter。

public sealed class VisibilityToBorderThicknessConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        try
        {
            var flag = (Visibility)value;
            if (flag == Visibility.Visible)
                return new Thickness(0);
            else
                return new Thickness(1);
        }
        catch
        {
            return new Thickness(0);
        }
    }
    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
          throw new NotImplementedException();
    }
}

还有你的 xaml：

 <ScrollViewer Name="blah">
      <Border BorderThickness="{Binding ElementName=blah, Path=VerticalScrollBarVisibility , Converter={StaticResources VisibilityToBorder}}">
 </ScrollViewer>

不要忘记将你的转换器添加到资源中！

GL&HF