一、代码

<Window x:Class="学习.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:学习"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">

    <Window.Resources>
        <Style x:Key="BaseButtonStytle" TargetType="Button"><!--创建一个按键的公用基础样式-->
            <Setter Property="FontSize" Value="20"/><!--字体大小-->
            <Setter Property="Foreground" Value="Black"/><!--字体颜色-->
            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Background" Value="LightBlue"/> <!--鼠标悬浮会变蓝色-->
                </Trigger>
            </Style.Triggers>
        </Style>

        <Style x:Key="ButtonStytle" TargetType="Button" BasedOn="{StaticResource BaseButtonStytle}"><!--继承共用基础样式的按键样式-->
            <Setter Property="Background" Value="Green"/><!--按键背景为绿色-->
        </Style>
    </Window.Resources>
    <Grid>
        <StackPanel>
            <Button Content="111" Style="{StaticResource ButtonStytle}" />
            <Button Content="111" Style="{StaticResource ButtonStytle}" />
            <Button Content="111" Style="{StaticResource ButtonStytle}" />
        </StackPanel>
    </Grid>
</Window>

二、结果