使用祖先RelativeSource绑定的Silverlight 5 DataGrid中的展开/折叠按钮

Question

我发现了几篇关于在SL3和SL4中实现展开/折叠的文章，这些文章实际上是缺少“祖先RelativeSource绑定”的解决方法。所以现在SL5不在了，我想知道SL5是如何实现的。

这里是SL4应答： Expand/Collapse button in a Silverlight DataGrid

Answer 1

随着SL5 RelativeSource很容易做到这一点：

<sdk:DataGrid ItemsSource="{Binding Items}" 
    AutoGenerateColumns="False" 
    RowDetailsVisibilityMode="Collapsed"> 
    <sdk:DataGrid.Resources> 
    <SL5:VisibilityToBoolConverter x:Key="converter"/> 
    </sdk:DataGrid.Resources> 
    <sdk:DataGrid.Columns> 
     <sdk:DataGridTemplateColumn> 
     <sdk:DataGridTemplateColumn.CellTemplate> 
      <DataTemplate> 
       <ToggleButton Content="Expand" 
        IsChecked="{Binding Path=DetailsVisibility, 
        Mode=TwoWay, 
        RelativeSource={RelativeSource AncestorType=sdk:DataGridRow}, 
        Converter={StaticResource converter}}"/> 
      </DataTemplate> 
      </sdk:DataGridTemplateColumn.CellTemplate> 
     </sdk:DataGridTemplateColumn> 
    </sdk:DataGrid.Columns> 
</sdk:DataGrid> 

但你需要一个Visibity到Boolean转换器，使其工作：

public class VisibilityToBoolConverter : IValueConverter 
{ 
    public object Convert(object value, Type targetType, object parameter, 
     CultureInfo culture) 
    { 
     Visibility visibility = (Visibility)value; 
     return (visibility == Visibility.Visible); 
    } 

    public object ConvertBack(object value, Type targetType, object parameter, 
     CultureInfo culture) 
    { 
     bool visibility = (bool)value; 
     return visibility ? Visibility.Visible : Visibility.Collapsed; 
    } 
}