如何定制和重用DataGridColumnHeader样式？

Question

我正在尝试自定义DataGrid的列标题，以显示子列标题，如以下屏幕截图所示：

​

我已经为两个子列创建了一个样式，如下所示：

<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"
xmlns:primitives="clr-namespace:System.Windows.Controls.Primitives;assembly=System.Windows.Controls.Data"
xmlns:sl="clr-namespace:UI" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" x:Class="UI.ColumnHeaderGrid"
mc:Ignorable="d">
<UserControl.Resources>
    <Style x:Key="SplitColumnHeaderStyle" TargetType="primitives:DataGridColumnHeader">
        <Setter Property="Foreground" Value="#FF000000"/>
        <Setter Property="HorizontalContentAlignment" Value="Center"/>
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="IsTabStop" Value="False"/>
        <Setter Property="SeparatorBrush" Value="#FFC9CACA"/>
        <Setter Property="Padding" Value="4"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="primitives:DataGridColumnHeader">
                    <Grid x:Name="Root">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition/>
                            <ColumnDefinition Width="Auto"/>
                        </Grid.ColumnDefinitions>
                        <Rectangle x:Name="BackgroundRectangle" Fill="#FF1F3B53" Stretch="Fill" Grid.ColumnSpan="2"/>
                        <Rectangle x:Name="BackgroundGradient" Stretch="Fill" Grid.ColumnSpan="2">
                            <Rectangle.Fill>
                                <LinearGradientBrush EndPoint=".7,1" StartPoint=".7,0">
                                    <GradientStop Color="#FCFFFFFF" Offset="0.015"/>
                                    <GradientStop Color="#F7FFFFFF" Offset="0.375"/>
                                    <GradientStop Color="#E5FFFFFF" Offset="0.6"/>
                                    <GradientStop Color="#D1FFFFFF" Offset="1"/>
                                </LinearGradientBrush>
                            </Rectangle.Fill>
                        </Rectangle>
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition/>
                                <ColumnDefinition Width="1"/>
                                <ColumnDefinition/>
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition/>
                                <RowDefinition/>
                                <RowDefinition/>
                            </Grid.RowDefinitions>
                            <TextBlock Grid.Row="0" Grid.ColumnSpan="3" Text="Headers" TextAlignment="Center"/>
                            <Rectangle Grid.Row="1" Grid.ColumnSpan="3" Fill="{TemplateBinding SeparatorBrush}" Height="1"/>
                            <TextBlock Grid.Row="2" Grid.Column="0" Text="Header 1" TextAlignment="Center"/>
                            <Rectangle Grid.Row="2" Grid.Column="1" Fill="{TemplateBinding SeparatorBrush}" Width="1"/>
                            <TextBlock Grid.Row="2" Grid.Column="2" Text="Header 2" TextAlignment="Center"/>
                            <Path x:Name="SortIcon" Grid.Column="2" Fill="#FF444444" Stretch="Uniform" HorizontalAlignment="Left" Margin="4,0,0,0" VerticalAlignment="Center" Width="8" Opacity="0" RenderTransformOrigin=".5,.5" Data="F1 M -5.215,6.099L 5.215,6.099L 0,0L -5.215,6.099 Z "/>
                        </Grid>
                        <Rectangle x:Name="VerticalSeparator" Fill="{TemplateBinding SeparatorBrush}" VerticalAlignment="Stretch" Width="1" Visibility="{TemplateBinding SeparatorVisibility}" Grid.Column="1"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</UserControl.Resources>
<data:DataGrid x:Name="LayoutRoot">
    <data:DataGrid.Columns>
        <data:DataGridTemplateColumn HeaderStyle="{StaticResource SplitColumnHeaderStyle}">
            <data:DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition/>
                            <ColumnDefinition/>
                        </Grid.ColumnDefinitions>
                        <Border Grid.Column="0" BorderBrush="#FFC9CACA" BorderThickness="0,0,0,0">
                            <TextBlock Grid.Column="0" Text="{Binding GridData.Column1}"/>
                        </Border>
                        <Border Grid.Column="1" BorderBrush="#FFC9CACA" BorderThickness="1,0,0,0">
                            <TextBlock Grid.Column="0" Text="{Binding GridData.Column2}"/>
                        </Border>
                    </Grid>
                </DataTemplate>
            </data:DataGridTemplateColumn.CellTemplate>
        </data:DataGridTemplateColumn>
    </data:DataGrid.Columns>
</data:DataGrid>

​

现在我想重用和扩展这种样式，以支持2->6个子列标题，但我不知道是否有方法可以做到这一点，比如ContentPresenter“覆盖”：

<Style x:Key="SplitColumnHeaderStyle" TargetType="primitives:DataGridColumnHeader">
    <Setter property="Template">
        <Setter.Value>
            ...
            <ContentPresenter Content="{TemplateBinding Content}".../>
            ...
        </Setter.Value>
    </Setter>
</Style>

<Style x:Key="TwoSubColumnHeaderStyle" BasedOn="SplitColumnHeaderStyle">
    <Setter property="Content">
        <Setter.Value>
            <Grid 2x2.../>
        </Setter.Value>
    </Setter>
</Style>

<Style x:Key="ThreeSubColumnHeaderStyle" BasedOn="SplitColumnHeaderStyle">
    <Setter property="Content">
        <Setter.Value>
            <Grid 2x3.../>
        </Setter.Value>
    </Setter>
</Style>

无论如何，请在这些问题上帮助我：

1. 给出了上面的模板，如何支持更多的子列标题，而不必为每个子列标题创建新的模板？
2. 假设上面的问题已经解决。如何在样式之外附加列名？
3. 我发现XAML中的一些部件、属性和可视化规则只是从原始Silverlight组件的样式复制过来的，即BackgroundGradient、BackgroundRectangle、VisualStateManager……它们必须在那里才能支持默认行为或效果，但是...有谁知道如何删除它们，但保留所有的默认behaviors/effects?

请具体一点，因为我刚刚开始使用C#和Silverlight。

Answer 1

这里有一个很好的例子：http://weblogs.asp.net/dwahlin/archive/2009/06/11/customizing-silverlight-3-datagrid-headers.aspx