怎么修改饼状图各块的颜色？
win 8 商店应用程序：
目前效果如下：

我想把它的红蓝色块改成别的颜色，请问怎么改，如下是代码：


CS代码：

/// <summary>

        /// 饼状图

        /// </summary>

        private void UpdateCharts()

        {

            List<NameValueItem> items = new List<NameValueItem>();

            NameValueItem nv = new NameValueItem();

            nv.Value = Convert.ToInt32(20);

            nv.Name = nv.Value.ToString() +  "%   及格比例";



            NameValueItem nv1 = new NameValueItem();

            nv1.Value = Convert.ToInt32(100 - Convert.ToInt32(20));

            nv1.Name = nv1.Value.ToString() + "%   不及格比例";

            items.Add(nv);

            items.Add(nv1);

            ((PieSeries)this.PieChart.Series[0]).ItemsSource = items;

            

        }

        public class NameValueItem

        {

            public string Name { get; set; }

            public int Value { get; set; }

        }

XAML代码：

<Charting:Chart

                             Grid.Row="1" Grid.Column="0"

                            HorizontalAlignment="Left"

                            Width="500"

                            x:Name="PieChart"

                            Title="" Foreground="Black" FontSize="12">

                            <Charting:Chart.Series>

                                <Series:PieSeries

                            Title="Population"

                            ItemsSource="{Binding Items}"

                            IndependentValueBinding="{Binding Name}"

                            DependentValueBinding="{Binding Value}"

                            IsSelectionEnabled="True"/>

                            </Charting:Chart.Series>

                        </Charting:Chart>

------解决方案--------------------
看半天了就是不会