正如 Nitesh 所说,您在按钮上没有 CornerRadius 属性,它是您在第一个样式中显示的 Border 的属性,只需复制您的第一个样式并更改 CornerRadius,然后将其分配给适当的样式按钮。
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style TargetType="Button" x:Key="TabButton">
<Setter Property="Background" Value="White" />
<Setter Property="TextBlock.TextAlignment" Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border CornerRadius="0" Background="White" BorderBrush="#ccc" BorderThickness="0,1,1,0" >
<ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="Button" x:Key="TabButtonFirst">
<Setter Property="Background" Value="White" />
<Setter Property="TextBlock.TextAlignment" Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border CornerRadius="3,0,0,0" Background="White" BorderBrush="#ccc" BorderThickness="0,1,1,0" >
<ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="Button" x:Key="TabButtonLast">
<Setter Property="Background" Value="White" />
<Setter Property="TextBlock.TextAlignment" Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border CornerRadius="0,0,0,3" Background="White" BorderBrush="#ccc" BorderThickness="0,1,1,0" >
<ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<Grid Background="Black">
<Button Style="{StaticResource TabButton}" Content="Button" Height="23" HorizontalAlignment="Left" Margin="12,72,0,0" Name="button1" VerticalAlignment="Top" Width="75" />
<Button Style="{StaticResource TabButtonFirst}" Content="Button" Height="23" HorizontalAlignment="Left" Margin="10,43,0,0" Name="button2" VerticalAlignment="Top" Width="75" />
<Button Style="{StaticResource TabButtonLast}" Content="Button" Height="23" HorizontalAlignment="Left" Margin="12,101,0,0" Name="button3" VerticalAlignment="Top" Width="75" />
</Grid>
</Window>