如何在WPF中为选项卡控件提供自定义形状？

<Window x:Class="CustomTabControl.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="TabItem">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="TabItem">
                        <Border Name="Border" Margin="0,0,-4,0" CornerRadius="10,10,0,0" Background="LightGray" BorderBrush="Black" BorderThickness="1">
                            <DockPanel>
                                <ContentPresenter x:Name="ContentSite"
                                                  VerticalAlignment="Center"
                                                  HorizontalAlignment="Center"
                                                  ContentSource="Header"
                                                  Margin="12,2,12,2"/>
                            </DockPanel>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsSelected" Value="True">
                                <Setter TargetName="Border" Property="Background" Value="White"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <TabControl>
            <TabItem Header="Tab 1">
                <TextBlock Text="Content of Tab 1"/>
            </TabItem>
            <TabItem Header="Tab 2">
                <TextBlock Text="Content of Tab 2"/>
            </TabItem>
        </TabControl>
    </Grid>
</Window>