1.btn {
2 display:block;
3 height: 300px;
4 width: 300px;
5 border-radius: 50%;
6 border: 1px solid red;
7
8}
1<Style TargetType="Button" x:Key="RoundButton">
2 <Style.Resources>
3 <Style TargetType="Border">
4 <Setter Property="CornerRadius" Value="5" />
5 </Style>
6 </Style.Resources>
7</Style>
8