WPF圆形按钮

<Window x:Class="RFMatrix.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:RFMatrix"
        mc:Ignorable="d"
        Title="MainWindow" Height="433.125" Width="411.875">
    <Grid x:Name="LayoutRoot">

        <Grid.RowDefinitions>
            <RowDefinition/>
        </Grid.RowDefinitions>

        <Button Grid.Column="0" Grid.Row="0" Height="400" Width="400" HorizontalAlignment="Left" VerticalAlignment="Top" Content="Button" Template="{DynamicResource ButtonControlTemplate1}" Cursor="Hand">
            <Button.Resources>
                <ControlTemplate x:Key="ButtonControlTemplate1" TargetType="{x:Type Button}">
                    <Grid>
                        <Ellipse x:Name="ButtonEllipse" Width="Auto" Height="Auto" StrokeThickness="4" Fill="White" Stroke="Gray"></Ellipse>
                        <Polygon x:Name="ButtonPolygon" Points="20,200 300,50 300,350" Stroke="White" StrokeThickness="2">
                            <Polygon.Fill>
                                <SolidColorBrush Color="Gray" Opacity="0.4"/>
                            </Polygon.Fill>
                        </Polygon>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="ButtonPolygon" Property="Fill" Value="Black"></Setter>
                        </Trigger>
                        <Trigger Property="IsPressed" Value="True">
                            <Setter TargetName="ButtonPolygon" Property="Fill" Value="Gray"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Button.Resources>
        </Button>
    </Grid>
</Window>