如何修改WPF中ComboBox下拉选中项颜色及右侧箭头颜色？

1. 修改下拉菜单选中项的淡蓝色样式 #

默认的选中高亮样式需要通过扩展ComboBoxItem的样式来覆盖，你可以在现有ItemContainerStyle中添加触发器，或者重写控件模板彻底替换样式：

方法一：使用触发器快速修改 #

<ComboBox Foreground="White" Name="comboBoxStatus" SelectedValue="{Binding SelectedContact.Status, Mode=TwoWay, UpdateSourceTrigger=Explicit}">
    <ComboBox.ItemContainerStyle>
        <Style TargetType="{x:Type ComboBoxItem}">
            <Setter Property="Background" Value="#3E4147" />
            <Setter Property="BorderBrush" Value="#292B2F" />
            <Setter Property="Foreground" Value="White" />
            <!-- 选中状态样式 -->
            <Style.Triggers>
                <Trigger Property="IsSelected" Value="True">
                    <Setter Property="Background" Value="#你的自定义选中背景色" />
                    <Setter Property="Foreground" Value="#你的自定义文字颜色" />
                    <Setter Property="BorderBrush" Value="#你的自定义边框色" />
                </Trigger>
                <!-- 可选：添加鼠标悬停样式 -->
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Background" Value="#你的悬停背景色" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </ComboBox.ItemContainerStyle>
</ComboBox>

替换代码中的#你的自定义颜色为你需要的颜色值即可覆盖默认淡蓝色选中样式。

方法二：重写ControlTemplate彻底替换（无残留样式） #

如果触发器无法覆盖所有默认效果，可以重写ComboBoxItem的模板：

<ComboBox.ItemContainerStyle>
    <Style TargetType="{x:Type ComboBoxItem}">
        <Setter Property="Background" Value="#3E4147" />
        <Setter Property="BorderBrush" Value="#292B2F" />
        <Setter Property="Foreground" Value="White" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ComboBoxItem}">
                    <Border x:Name="Bd" 
                            Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Padding="{TemplateBinding Padding}"
                            SnapsToDevicePixels="True">
                        <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                          VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                                          SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsSelected" Value="True">
                            <Setter TargetName="Bd" Property="Background" Value="#你的选中背景色" />
                            <Setter TargetName="Bd" Property="Foreground" Value="White" />
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="Bd" Property="Background" Value="#你的悬停背景色" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ComboBox.ItemContainerStyle>

2. 修改ComboBox右侧箭头的颜色 #

ComboBox的箭头属于控件模板的一部分，需要重写ComboBox的模板来修改：

<ComboBox Foreground="White" Name="comboBoxStatus" SelectedValue="{Binding SelectedContact.Status, Mode=TwoWay, UpdateSourceTrigger=Explicit}">
    <ComboBox.Template>
        <ControlTemplate TargetType="{x:Type ComboBox}">
            <Grid x:Name="MainGrid" SnapsToDevicePixels="True">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0" />
                </Grid.ColumnDefinitions>
                <!-- 输入框区域 -->
                <Border x:Name="Border" Background="#3E4147" BorderBrush="#292B2F" BorderThickness="1">
                    <TextBox x:Name="PART_EditableTextBox" 
                             HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                             Margin="{TemplateBinding Padding}"
                             VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                             Background="{TemplateBinding Background}"
                             Foreground="{TemplateBinding Foreground}"
                             IsReadOnly="{TemplateBinding IsReadOnly}" />
                </Border>
                <!-- 箭头按钮 -->
                <ToggleButton x:Name="ToggleButton" 
                              Grid.Column="1"
                              Background="#3E4147"
                              BorderBrush="#292B2F"
                              BorderThickness="1"
                              Foreground="#你的箭头颜色"
                              Focusable="False"
                              IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
                    <ToggleButton.Template>
                        <ControlTemplate TargetType="{x:Type ToggleButton}">
                            <Border x:Name="Bd" 
                                    Background="{TemplateBinding Background}"
                                    BorderBrush="{TemplateBinding BorderBrush}"
                                    BorderThickness="{TemplateBinding BorderThickness}"
                                    SnapsToDevicePixels="True">
                                <!-- 箭头路径，Fill绑定ToggleButton的Foreground -->
                                <Path x:Name="Arrow" 
                                      Data="M0,0L4,4L8,0Z" 
                                      Fill="{TemplateBinding Foreground}"
                                      HorizontalAlignment="Center"
                                      VerticalAlignment="Center"
                                      Width="8" Height="4" />
                            </Border>
                            <ControlTemplate.Triggers>
                                <Trigger Property="IsChecked" Value="True">
                                    <Setter TargetName="Arrow" Property="Data" Value="M0,4L4,0L8,4Z" />
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </ToggleButton.Template>
                </ToggleButton>
                <!-- 下拉弹窗 -->
                <Popup x:Name="PART_Popup" 
                       AllowsTransparency="True"
                       Grid.ColumnSpan="2"
                       IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}"
                       PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}"
                       Placement="Bottom">
                    <Themes:SystemDropShadowChrome x:Name="Shdw" 
                                                   Color="Transparent"
                                                   MaxHeight="{TemplateBinding MaxDropDownHeight}"
                                                   MinWidth="{Binding ActualWidth, ElementName=MainGrid}">
                        <Border x:Name="DropDownBorder" Background="#3E4147" BorderBrush="#292B2F" BorderThickness="1">
                            <ScrollViewer x:Name="DropDownScrollViewer">
                                <ItemsPresenter x:Name="ItemsPresenter" 
                                               KeyboardNavigation.DirectionalNavigation="Contained"
                                               SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                            </ScrollViewer>
                        </Border>
                    </Themes:SystemDropShadowChrome>
                </Popup>
            </Grid>
        </ControlTemplate>
    </ComboBox.Template>
    <!-- 保留你原有的ItemContainerStyle -->
    <ComboBox.ItemContainerStyle>
         <Style TargetType="{x:Type ComboBoxItem}">
              <Setter Property="Background" Value="#3E4147" />
              <Setter Property="BorderBrush" Value="#292B2F" />
              <!-- 这里可以继续添加选中状态触发器 -->
         </Style>
     </ComboBox.ItemContainerStyle>
</ComboBox>

修改ToggleButton的Foreground属性值，箭头会自动继承该颜色；如果需要单独设置箭头颜色，直接修改Path的Fill属性为固定颜色即可。

内容的提问来源于stack exchange，提问作者povodnikt