如何使用扩展的WPF工具包创建简单的饼图

<Window x:Class="PieChartExample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        Title="Pie Chart Example" Height="450" Width="800">
    <Grid>
        <xctk:PieChart Title="Sales by Region" Height="400" Width="400">
            <xctk:PieChart.Series>
                <xctk:PieSeries Title="North" DisplayMember="Region" ValueMember="Sales">
                    <xctk:PieSeries.ItemsSource>
                        <x:Array Type="{x:Type xctk:PieSegment}">
                            <xctk:PieSegment Region="Region A" Sales="100" />
                            <xctk:PieSegment Region="Region B" Sales="200" />
                            <xctk:PieSegment Region="Region C" Sales="150" />
                        </x:Array>
                    </xctk:PieSeries.ItemsSource>
                </xctk:PieSeries>
            </xctk:PieChart.Series>
        </xctk:PieChart>
    </Grid>
</Window>