wpf在界面上绘制圆形按钮

<Window.Resources>
        <Style x:Key="RoundedGelButton" TargetType="Button">
            <Setter Property="Width" Value="35"/>
            <Setter Property="Height" Value="35"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Grid>
                            <Ellipse Name="GelBackground" StrokeThickness="0.5" Fill="Green" >
                            </Ellipse>
                            <ContentPresenter Name="GelButtonContent" VerticalAlignment="Center" HorizontalAlignment="Center"
                                           Content="{TemplateBinding Content}"/>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <Style x:Key="RoundedGelButton2" TargetType="Button">
            <Setter Property="Width" Value="35"/>
            <Setter Property="Height" Value="35"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Grid>
                            <Ellipse Name="GelBackground" StrokeThickness="0.5" Fill="Red" >
                            </Ellipse>
                            <ContentPresenter Name="GelButtonContent" VerticalAlignment="Center" HorizontalAlignment="Center"
                                           Content="{TemplateBinding Content}"/>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>