WindowsFormsTest/WpfTest/MainWindow.xaml

<Window x:Class="WpfTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfTest" xmlns:wpf="clr-namespace:Microsoft.Web.WebView2.Wpf;assembly=Microsoft.Web.WebView2.Wpf"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800" Loaded="Window_Loaded">
    <Grid>
        <wpf:WebView2 x:Name="PdfWebView" Margin="112,10,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Width="600" Height="400" />
        <Grid Visibility="Collapsed" Width="300" Height="300" Margin="481,77,19,58"/>
        <ComboBox Name="testcombo" Height="60" Width="100" Loaded="testcombo_Loaded" Margin="8,196,692,179" >
            <ComboBox.ItemContainerStyle>
                <Style TargetType="ComboBoxItem">
                    <Setter Property="Background" Value="#FF0087FF" />
                    <Style.Triggers>
                        <Trigger Property="IsHighlighted" Value="True">
                            <Setter Property="Background" Value="#FF0087FF" />
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </ComboBox.ItemContainerStyle>
        </ComboBox>
        <ComboBox  Height="60" Width="100" Margin="6,29,0,0" HorizontalAlignment="Left" VerticalAlignment="Top">
            <ComboBox.Style>
                <Style TargetType="ComboBox">
                    <!-- 设置ComboBox本身背景色 -->
                    <Setter Property="Background" Value="Blue" />
                    <Setter Property="Foreground" Value="White" />
                </Style>
            </ComboBox.Style>

            <!-- 设置下拉框部分的样式 -->
            <ComboBox.ItemContainerStyle>
                <Style TargetType="ComboBoxItem">
                    <Setter Property="Background" Value="Blue" />
                    <Setter Property="Foreground" Value="White" />
                    <Style.Triggers>
                        <Trigger Property="IsHighlighted" Value="True">
                            <Setter Property="Background" Value="LightBlue" />
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </ComboBox.ItemContainerStyle>
            <ComboBoxItem>1</ComboBoxItem>
            <ComboBoxItem>2</ComboBoxItem>
        </ComboBox>
        <ComboBox Height="60" Width="100" Margin="4,111,696,264">
            <ComboBox.Template>
                <ControlTemplate TargetType="ComboBox">
                    <Grid>
                        <ToggleButton x:Name="ToggleButton" 
                              Background="Blue"
                              Foreground="White"
                              IsChecked="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}"
                              ClickMode="Press">
                            <ToggleButton.Template>
                                <ControlTemplate TargetType="ToggleButton">
                                    <Border x:Name="Border" Background="Blue" BorderBrush="DarkBlue" BorderThickness="1">
                                        <Grid>
                                            <Grid.ColumnDefinitions>
                                                <ColumnDefinition />
                                                <ColumnDefinition Width="20" />
                                            </Grid.ColumnDefinitions>
                                            <ContentPresenter Grid.Column="0" Margin="3" />
                                            <Path x:Name="Arrow" Grid.Column="1" 
                                          Fill="White"
                                          HorizontalAlignment="Center" 
                                          VerticalAlignment="Center"
                                          Data="M 0 0 L 4 4 L 8 0 Z" />
                                        </Grid>
                                    </Border>
                                    <ControlTemplate.Triggers>
                                        <Trigger Property="IsMouseOver" Value="True">
                                            <Setter TargetName="Border" Property="Background" Value="LightBlue" />
                                        </Trigger>
                                    </ControlTemplate.Triggers>
                                </ControlTemplate>
                            </ToggleButton.Template>
                        </ToggleButton>
                        <ContentPresenter x:Name="ContentSite" 
                                  IsHitTestVisible="False"
                                  Content="{TemplateBinding SelectionBoxItem}"
                                  ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
                                  Margin="3,3,23,3"
                                  VerticalAlignment="Center"
                                  HorizontalAlignment="Left" 
                                  TextBlock.Foreground="White"/>
                        <Popup x:Name="Popup" 
                       Placement="Bottom"
                       IsOpen="{TemplateBinding IsDropDownOpen}"
                       AllowsTransparency="True" 
                       Focusable="False"
                       PopupAnimation="Slide">
                            <Border x:Name="DropDownBorder" 
                            Background="Blue"
                            BorderBrush="DarkBlue"
                            BorderThickness="1">
                                <ScrollViewer Margin="0,3,0,3" 
                                      SnapsToDevicePixels="True">
                                    <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" />
                                </ScrollViewer>
                            </Border>
                        </Popup>
                    </Grid>
                </ControlTemplate>
            </ComboBox.Template>

            <ComboBox.ItemContainerStyle>
                <Style TargetType="ComboBoxItem">
                    <Setter Property="Background" Value="Blue" />
                    <Setter Property="Foreground" Value="White" />
                    <Style.Triggers>
                        <Trigger Property="IsHighlighted" Value="True">
                            <Setter Property="Background" Value="LightBlue" />
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </ComboBox.ItemContainerStyle>
        </ComboBox>
        <Button Content="Button" Height="40" Margin="20,280,0,0" Width="75" VerticalAlignment="Top" HorizontalAlignment="Left" Click="Button_Click" />
        <Popup Name="myPopup" Placement="Mouse" AllowsTransparency="True">
            <Border Background="LightYellow" BorderBrush="Gray" BorderThickness="1">
                <TextBlock Text="这是一个悬浮提示" Padding="10"/>
            </Border>
        </Popup>
    </Grid>
</Window>