如何在样式中使用已设置的 ItemSsource

Question

我的问题是如何在Style 中引用我已经在Window 上设置的ItemsSource？我有以下ListViews：

AppointmentOverview.xaml

    <ListView Grid.Column="1" Grid.Row="3" ItemsSource="{Binding Mov}"/>
    <ListView Grid.Column="1" Grid.Row="4" ItemsSource="{Binding Mon}"/>
    <ListView Grid.Column="2" Grid.Row="3" ItemsSource="{Binding Div}"/>
    <ListView Grid.Column="2" Grid.Row="4" ItemsSource="{Binding Din}"/>
    <ListView Grid.Column="3" Grid.Row="3" ItemsSource="{Binding Miv}"/>
    <ListView Grid.Column="3" Grid.Row="4" ItemsSource="{Binding Min}"/>
    <ListView Grid.Column="4" Grid.Row="3" ItemsSource="{Binding Dov}"/>
    <ListView Grid.Column="4" Grid.Row="4" ItemsSource="{Binding Don}"/>
    <ListView Grid.Column="5" Grid.Row="3" ItemsSource="{Binding Frv}"/>
    <ListView Grid.Column="5" Grid.Row="4" ItemsSource="{Binding Frn}"/>

如您所见，每个ListView 都有不同的ItemsSource，所以我无法通过Style 设置ItemsSource。但他们都有相同的Style。这个Style 应该包含一个Composite Collection。 Composite Collection 应该包含这个ItemsSource + 一个Button。我的问题是如何告诉CollectionViewSource 它应该使用已经设置的ItemsSource？我的Styles 位于不同的文件中。

Styles.xaml

<Style TargetType="{x:Type ListView}">
    <Setter Property="ItemsPanel">
        <Setter.Value>
            <ItemsPanelTemplate>
                <UniformGrid Rows="5" Columns="1"/>
            </ItemsPanelTemplate>
        </Setter.Value>
    </Setter>
    <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Disabled"/>
    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled"/>        
</Style>

<Style TargetType="{x:Type ListViewItem}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ListViewItem}">
                <Border BorderBrush="#5076A7" BorderThickness="1">
                    <Border.Background>
                        <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                            <GradientStop Color="#FFFFFF" Offset="0.0"/>
                            <GradientStop Color="#C0D3EA" Offset="1.0"/>
                        </LinearGradientBrush>
                    </Border.Background>
                    <StackPanel TextElement.FontFamily="Segoe UI" TextElement.FontSize="12">
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*"/>
                                <ColumnDefinition Width="15"/>
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="*"/>
                            </Grid.RowDefinitions>
                            <TextBlock Padding="3,0,0,0" Text="{Binding Betreff}" TextTrimming="CharacterEllipsis" Grid.Column="0" Grid.Row="0"/>
                            <Button FontSize="7" Content="X" Grid.Column="1" Grid.Row="0" 
                                    Command="{Binding DataContext.DeleteButtonCommand, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" 
                                    CommandParameter="{Binding ItemId}"/>
                        </Grid>
                        <TextBlock Padding="3,0,0,0" Text="{Binding Kunde}"/>
                        <StackPanel Orientation="Horizontal">
                            <TextBlock FontWeight="Bold" Padding="3,0,0,0" Text="{Binding Ort}"/>
                            <TextBlock Padding="3,0,0,0" Text="("/>
                            <TextBlock Text="{Binding Alternative}"/>
                            <TextBlock Text=")"/>
                        </StackPanel>
                    </StackPanel>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <DataTrigger Binding="{Binding Betreff}" Value="Blocked">
            <Setter Property="Template" Value="{StaticResource BlockedListViewItem}"/>
        </DataTrigger>
    </Style.Triggers>
</Style>

Answer 1

您可以创建一个附加属性来保留初始集合，以避免与将在样式中注入的集合发生冲突。您必须创建一个新的 DependencyObject 类或在现有的类中定义它：

public class Extensions : DependencyObject
{

    #region MyItemsSource

    /// <summary>
    /// MyItemsSource Attached Dependency Property
    /// </summary>
    public static readonly DependencyProperty MyItemsSourceProperty =
        DependencyProperty.RegisterAttached("MyItemsSource", typeof(IEnumerable), typeof(Extensions),
            new FrameworkPropertyMetadata((IEnumerable)null));

    /// <summary>
    /// Gets the MyItemsSource property. This dependency property 
    /// indicates ....
    /// </summary>
    public static IEnumerable GetMyItemsSource(DependencyObject d)
    {
        return (IEnumerable)d.GetValue(MyItemsSourceProperty);
    }

    /// <summary>
    /// Sets the MyItemsSource property. This dependency property 
    /// indicates ....
    /// </summary>
    public static void SetMyItemsSource(DependencyObject d, IEnumerable value)
    {
        d.SetValue(MyItemsSourceProperty, value);
    }

    #endregion


}

现在在 XAML 中，ListView 将如下所示：

<ListView  local:Extensions.MyItemsSource="{Binding Items}" Style="{StaticResource ListBox_Style}"/>

要真正将 ItemsSource 绑定到 CompositeCollection 内的 MyItemsSource 属性，没有简单的解决方案。 CompositeCollection 不是 Visual 对象，甚至不是 DependencyProperty，因此不可能进行 findAncestor 绑定。在这种情况下，使用 CollectionViewSource 作为样式的资源将不起作用。

这里需要一些解决方法。一种可能性是使用转换器：

public class CollectionConverter : IValueConverter
{
    public ControlTemplate AdditionalControlTemplate { get; set; }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {

        CompositeCollection cc = new CompositeCollection();

        //Add base ItemSource
        CollectionContainer cont = new CollectionContainer();
        cont.Collection = (IEnumerable)value;
        cc.Add(cont);

        //Add a control at the end
        if(AdditionalControlTemplate != null)
            cc.Add(new Control() { Template = AdditionalControlTemplate });

        return cc;

    }

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

此转换器获取源集合并将其注入到 CompositeCollection。然后使用可以在转换器外部指定的模板将控件添加到此集合中。所以你的按钮可以进入这个 ControlTemplate。 ListView 样式将如下所示：

<Style x:Key="ListBox_Style" TargetType="{x:Type ListView}">
    <Style.Resources>
        <!-- Control template for the object to be added at the end of the ListView -->
        <ControlTemplate x:Key="AdditionalButtonTemplate" TargetType="{x:Type Control}">
            <Button Content="Hello World!"/>
        </ControlTemplate>
        <local:CollectionConverter x:Key="CollectionConverter" AdditionalControlTemplate="{StaticResource AdditionalButtonTemplate}"/>
    </Style.Resources>

    <Setter Property="ItemsSource" Value="{Binding (local:Extensions.MyItemsSource), Converter={StaticResource CollectionConverter}, RelativeSource={RelativeSource Self}}"/>
</Style>

绕过 CompositeCollection 限制的更简单的解决方案是使用中间 ItemsControl。因此，您将使用 ItemsControl 而不是 ListView：

采用以下样式：

<Style x:Key="icListViewStyle" TargetType="{x:Type ItemsControl}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ItemsControl}">
                <ListView>
                    <ListView.Resources>
                        <CollectionViewSource x:Key="BaseItemsSource" Source="{Binding ItemsSource, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}, AncestorLevel=2}}"/>
                    </ListView.Resources>
                    <ListView.ItemsSource>
                        <CompositeCollection>
                            <CollectionContainer Collection="{Binding Source={StaticResource BaseItemsSource}}"/>
                            <Button Content="Hello World!"/>
                        </CompositeCollection>
                    </ListView.ItemsSource>
                </ListView>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

这里BaseItemsSource是ListView的资源，是一个实际的可视对象，所以RelativeSource可以在绑定中解析。