WPF如何通过代码实现Button对象的Template属性进行赋值

1、如何把[ellipse对象]添加到[button对象]的Template属性呢？

2、或者告诉我怎么样用代码动态的更改Button的ControlTemplate设置为这个ExternalProgramTemplate

/**
                    <Button Width="40" Height="40" Margin="30" Click="AddExternalProgram" >
                        <Button.Template>
                            <ControlTemplate>
                                <Grid>
                                    <Ellipse StrokeThickness="0.5" Margin="-20,-20"  >
                                        <Ellipse.Fill>
                                            <ImageBrush x:Name="ICON" ImageSource="Resources/添加提示.png"/>
                                        </Ellipse.Fill>
                                    </Ellipse>
                                    <Ellipse Margin="25,-10,-10,25" RenderTransformOrigin="0.5,0.5" >
                                        <Ellipse.RenderTransform>
                                            <TransformGroup>
                                                <ScaleTransform ScaleY="-1"/>
                                            </TransformGroup>
                                        </Ellipse.RenderTransform>
                                        <Ellipse.Fill>
                                            <ImageBrush x:Name="Del_Icon" ImageSource="Resources/举手.png"/>
                                        </Ellipse.Fill>
                                    </Ellipse>
                                </Grid>
                            </ControlTemplate>
                        </Button.Template>
                    </Button>
                 * */

                System.Windows.Controls.Button button = new System.Windows.Controls.Button();
                button.Margin = new Thickness(30, 30, 30, 30);
                button.Width = 40;
                button.Height = 40;
                button.Tag = appName;


                //=================================================================================================
                Ellipse ellipse1 = new Ellipse();
                ellipse1.StrokeThickness = 0.5;
                ellipse1.Margin = new Thickness(-20, -20, -20, -20);
                ImageBrush imageBrush1 = new ImageBrush();
                imageBrush1.ImageSource = GetIcon(appName);
                ellipse1.Fill = imageBrush1;
                ellipse1.MouseLeftButtonDown += ExternalProgramStartUp;

                FrameworkElementFactory f_Ellipse1 = new FrameworkElementFactory(typeof(Ellipse), "Ellipse_icon");
                f_Ellipse1.SetValue(Ellipse.StrokeThicknessProperty, 0.5);
                f_Ellipse1.SetValue(Ellipse.MarginProperty, new Thickness(-20, -20, -20, -20));
                f_Ellipse1.SetValue(Ellipse.FillProperty, imageBrush1);
                f_Ellipse1.SetValue(Ellipse.TagProperty, appName);
                // 单击按钮
                f_Ellipse1.AddHandler(MouseLeftButtonDownEvent, new MouseButtonEventHandler(ExternalProgramStartUp));



                // ================================================================================================

                Ellipse ellipse2 = new Ellipse();
                ellipse2.StrokeThickness = 0.5;
                ellipse2.Margin = new Thickness(25, -10, -10, 25);
                ellipse2.RenderTransformOrigin = new Point(0.5, 0.5);
                ellipse2.Visibility = Visibility.Hidden;
                ellipse2.MouseLeftButtonDown += DelExternalProgram;

                // 背景图片
                ImageBrush imageBrush2 = new ImageBrush();
                imageBrush2.ImageSource = BitMapUtil.ChangeBitmapToImageSource((System.Drawing.Bitmap)Resource.ResourceManager.GetObject("错误提示"));

                // 动画属性
                ScaleTransform sctr = new ScaleTransform();
                sctr.ScaleY = -1;
                TransformGroup trfg = new TransformGroup();
                trfg.Children.Add(sctr);
                ellipse2.RenderTransform = trfg;

                FrameworkElementFactory f_Ellipse2 = new FrameworkElementFactory(typeof(Ellipse), "Ellipse_del");
                f_Ellipse2.SetValue(Ellipse.StrokeThicknessProperty, 0.5);
                f_Ellipse2.SetValue(Ellipse.MarginProperty, new Thickness(25, -10, -10, 25));
                f_Ellipse2.SetValue(Ellipse.FillProperty, imageBrush2);
                f_Ellipse2.SetValue(Ellipse.RenderTransformProperty, trfg);
                f_Ellipse2.SetValue(Ellipse.VisibilityProperty, Visibility.Hidden);
                f_Ellipse2.AddHandler(MouseLeftButtonDownEvent, new MouseButtonEventHandler(DelExternalProgram));


                // ================================================================================================
                // Group容器
                FrameworkElementFactory f_Group = new FrameworkElementFactory(typeof(Grid), "Grid");


                f_Group.AppendChild(f_Ellipse1);
                f_Group.AppendChild(f_Ellipse2);

                ControlTemplate ct = new ControlTemplate(typeof(System.Windows.Controls.Button));
                ct.VisualTree = f_Group;

                button.Template = ct;
                // button.Click += ExternalProgramStartUp;
                this.ExternalProgram.Children.Add(button);

抄过来个答案:

private void Button_Loaded(object sender, RoutedEventArgs e) {
    var button = sender as Button;
    string template =
        "<ControlTemplate xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'
            TargetType=\"Button\">" +
            "<Border>" +
                 "<ContentPresenter/>" +
            "</Border>" +
        "</ControlTemplate>";
    button.Template = (ControlTemplate)XamlReader.Parse(template);
}