WPF ComboBox style

以下是一个简单的 WPF ComboBox 样式示例：

<Window.Resources>
    <Style x:Key="ComboBoxStyle" TargetType="{x:Type ComboBox}">
        <Setter Property="Foreground" Value="Black"/>
        <Setter Property="Background" Value="White"/>
        <Setter Property="FontSize" Value="14"/>
        <Setter Property="Padding" Value="5,2"/>
        <Setter Property="Height" Value="30"/>
        <Setter Property="Width" Value="120"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ComboBox}">
                    <Grid>
                        <ToggleButton x:Name="ToggleButton" BorderBrush="Gray" BorderThickness="1" Background="{TemplateBinding Background}" Foreground="{TemplateBinding Foreground}" Grid.Column="2" Focusable="false" IsChecked="{Binding Path=IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" >
                            <ToggleButton.Template>
                                <ControlTemplate>
                                    <Grid>
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition />
                                            <ColumnDefinition Width="20" />
                                        </Grid.ColumnDefinitions>
                                        <Border x:Name="Border" Background="{TemplateBinding Background}" BorderThickness="0" CornerRadius="0" Grid.ColumnSpan="2" />
                                        <Path x:Name="Arrow" Grid.Column="1" Fill="{TemplateBinding Foreground}" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 4 4 L 8 0 Z"/>
                                    </Grid>
                                    <ControlTemplate.Triggers>
                                        <Trigger Property="IsEnabled" Value="False">
                                            <Setter TargetName="Border" Property="Background" Value="#EEE" />
                                            <Setter TargetName="Border" Property="BorderBrush" Value="#AAA" />
                                            <Setter Property="Foreground" Value="#AAA"/>
                                            <Setter TargetName="Arrow" Property="Fill" Value="#AAA" />
                                        </Trigger>
                                        <Trigger Property="IsMouseOver" Value="True">
                                            <Setter TargetName="Border" Property="Background" Value="#DDD" />
                                        </Trigger>
                                        <Trigger Property="IsChecked" Value="True">
                                            <Setter TargetName="Border" Property="Background" Value="#EEE" />
                                        </Trigger>
                                    </ControlTemplate.Triggers>
                                </ControlTemplate>
                            </ToggleButton.Template>
                        </ToggleButton>
                        <Popup x:Name="Popup" Placement="Bottom" IsOpen="{TemplateBinding IsDropDownOpen}" AllowsTransparency="True" Focusable="False" PopupAnimation="Slide">
                            <Grid x:Name="DropDown" SnapsToDevicePixels="True" MinWidth="{TemplateBinding ActualWidth}" MaxHeight="{TemplateBinding MaxDropDownHeight}">
                                <Border x:Name="DropDownBorder" Background="White" BorderThickness="1" BorderBrush="Gray"/>
                                <ScrollViewer Margin="4,6,4,6" SnapsToDevicePixels="True">
                                    <ItemsPresenter SnapsToDevicePixels="True" />
                                </ScrollViewer>
                            </Grid>
                            <Popup.Style>
                                <Style TargetType="{x:Type Popup}">
                                    <Style.Triggers>
                                        <Trigger Property="HasDropShadow" Value="True">
                                            <Setter Property="Margin" Value="0,0,5,5" />
                                        </Trigger>
                                    </Style.Triggers>
                                </Style>
                            </Popup.Style>
                        </Popup>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Window.Resources>

<StackPanel>
    <ComboBox Style="{StaticResource ComboBoxStyle}" ItemsSource="{Binding Items}" SelectedItem="{Binding SelectedItem}" />
</StackPanel>

这个样式将 ComboBox 的默认外观替换为一个带有箭头的按钮，单击该按钮将显示一个下拉列表。你可以使用这个样式作为起点，自定义一些属性来满足你的需求。