stormchat/stormchat-client-csharp/StormChatWPF/UI/Style.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:local="clr-namespace:StormChatWPF.UI">
    <Style x:Key="DropDownMenu" TargetType="ComboBox">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ComboBox">
                    <Grid  Height="100" Width="100" Margin="0,0,0,0">
                        <ComboBox Width="Auto" Height="Auto" VerticalAlignment="Top" Margin="30,10,30,0" Visibility="Hidden"/>
                        <Image Width="Auto" Height="Auto" Source="pack://application:,,,/UI/Resources/闪电.png" Stretch="Fill" Margin="0" VerticalAlignment="Stretch"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>