AlternationConverter的使用

xaml

<Window.Resources>
    <AlternationConverter x:Key="AlternationConverter">
        <SolidColorBrush Color="Red" />
        <SolidColorBrush Color="Orange" />
        <SolidColorBrush Color="Yellow" />
        <SolidColorBrush Color="Green" />
        <SolidColorBrush Color="Cyan" />
        <SolidColorBrush Color="Blue" />
        <SolidColorBrush Color="Purple" />
    </AlternationConverter>
</Window.Resources>

<Grid>
    <ListBox x:Name="box" AlternationCount="7">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <Border
                    Width="10"
                    Height="10"
                    Background="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBoxItem}}, Path=(ItemsControl.AlternationIndex), Converter={StaticResource AlternationConverter}}" />
            </DataTemplate>
        </ListBox.ItemTemplate>
        <ListBox.ItemsPanel>
            <ItemsPanelTemplate>
                <StackPanel Orientation="Horizontal" />
            </ItemsPanelTemplate>
        </ListBox.ItemsPanel>
    </ListBox>
</Grid>

xaml.cs

box.ItemsSource = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };

效果