<ControlTemplate x:Key="CornerButton" TargetType="{x:Type Button}">
<Border Name="buttonborder" BorderBrush="Green" BorderThickness="0" CornerRadius="15" Background="#3A98FC">
<ContentPresenter Content="{TemplateBinding Content}" HorizontalAlignment="Center" VerticalAlignment="Center" />
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="buttonborder" Property="Background" Value="#3A98FF"/>
</Trigger>
<Trigger Property="IsPressed" Value="true">
<Setter TargetName="buttonborder" Property="Background" Value="Blue"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>

貢獻給大家 希望大家給我點個贊。

使用方法：   <Button   Foreground="White"  Template="{StaticResource CornerButton}" />