C# WPF ComboBox 复杂自定义弹出数据显示

Question

所以，有一个具有自定义组合框样式的程序，让它看起来更扁平。它显示用户名，最近收到了将某些东西添加到弹出框本身的请求，但在选择该项目时没有在“选择”框中显示信息。像这样（红框里的东西就是我要补充的）：

这个特定的组合框填充了一个作为自定义数据结构的项目源，所以我有数据，我只需要看看我该怎么做。

这是我的自定义样式：

    <Style x:Key="ComboBoxFlatStyle" TargetType="{x:Type ComboBox}">
        <Setter Property="UIElement.SnapsToDevicePixels" Value="True"/>
        <Setter Property="FrameworkElement.OverridesDefaultStyle" Value="True"/>
        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
        <Setter Property="ScrollViewer.CanContentScroll" Value="True"/>
        <Setter Property="FrameworkElement.FocusVisualStyle" Value="{x:Null}"/>
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ComboBox}">
                    <Grid>
                        <ToggleButton Name="ToggleButton" Grid.Column="2"
                                      ClickMode="Press"
                                      Focusable="False"
                                      IsChecked="{Binding Path=IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
                                      Template="{StaticResource ComboBoxToggleButtonTemplate}"/>

                        <ContentPresenter Name="ContentSite" Margin="5,3,23,3" IsHitTestVisible="False"
                                          HorizontalAlignment="Left" VerticalAlignment="Center"
                                          Content="{TemplateBinding ComboBox.SelectionBoxItem}"
                                          ContentTemplate="{TemplateBinding ComboBox.SelectionBoxItemTemplate}"
                                          ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"/>

                        <TextBox Name="PART_EditableTextBox" Margin="3,3,23,3"                     
                                 IsReadOnly="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=IsReadOnly}"
                                 Visibility="Hidden"
                                 Background="Transparent"
                                 Foreground="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=Foreground}"
                                 HorizontalAlignment="Left" VerticalAlignment="Center"
                                 Focusable="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=Focusable}">

                            <TextBox.Template>
                                <ControlTemplate TargetType="{x:Type TextBox}">
                                    <Border Name="PART_ContentHost"
                                            Focusable="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=Focusable}"/>
                                </ControlTemplate>
                            </TextBox.Template>
                        </TextBox>
                        <!-- Popup showing items -->
                        <Popup Name="Popup"
                               Placement="Bottom"
                               Focusable="False"
                               AllowsTransparency="True"
                               IsOpen="{TemplateBinding ComboBox.IsDropDownOpen}"
                               PopupAnimation="Slide">

                            <Grid Name="DropDown" SnapsToDevicePixels="True"
                                  MinWidth="{TemplateBinding FrameworkElement.ActualWidth}"
                                  MaxHeight="{TemplateBinding ComboBox.MaxDropDownHeight}">

                                <Border Name="DropDownBorder" Background="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=Background}"
                                        Margin="0,1,0,0"
                                        CornerRadius="0" BorderThickness="1,1,1,1"
                                        BorderBrush="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=BorderBrush}"/>

                                <ScrollViewer Margin="4" SnapsToDevicePixels="True">
                                    <StackPanel IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Contained" />
                                </ScrollViewer>
                            </Grid>
                        </Popup>
                    </Grid>

                    <ControlTemplate.Triggers>
                        <Trigger Property="ItemsControl.HasItems" Value="False">
                            <Setter Property="FrameworkElement.MinHeight" TargetName="DropDownBorder" 
                                    Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=MaxDropDownHeight}"/>
                        </Trigger>
                        <Trigger Property="UIElement.IsEnabled" Value="False">
                            <Setter Property="TextElement.Foreground" Value="{StaticResource ComboBoxDisabledForegroundBrush}"/>
                        </Trigger>
                        <Trigger Property="ItemsControl.IsGrouping" Value="True">
                            <Setter Property="ScrollViewer.CanContentScroll" Value="False"/>
                        </Trigger>
                        <Trigger Property="ComboBox.IsEditable" Value="True">
                            <Setter Property="KeyboardNavigation.IsTabStop" Value="False"/>
                            <Setter Property="UIElement.Visibility" TargetName="PART_EditableTextBox" Value="Visible"/>
                            <Setter Property="UIElement.Visibility" TargetName="ContentSite" Value="Hidden"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

Answer 1

在选择框中以不同方式显示项目的一种快速但有点脏的方法是通过ItemContainerStyle 设置项目模板：选择框内容不是 ComboBoxItem 的内容，因此不会应用模板。

<ComboBox
    VerticalAlignment="Top"
    ItemsSource="{Binding Items}"
    DisplayMemberPath="Name"
    HorizontalContentAlignment="Stretch"
    >
    <ComboBox.ItemContainerStyle>
        <Style TargetType="ComboBoxItem">
            <Setter Property="ContentTemplate">
                <Setter.Value>
                    <DataTemplate>
                        <DockPanel LastChildFill="False">
                            <ContentControl Content="{Binding Name}" DockPanel.Dock="Left" />
                            <ContentControl Content="{Binding Value}" DockPanel.Dock="Right" />
                        </DockPanel>
                    </DataTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </ComboBox.ItemContainerStyle>
</ComboBox>

但你不能使用ComboBox.ItemTemplate ；它将覆盖您通过样式应用的模板。更强大的solution is to write a template selector, as in this answer。