巧用Delegate在SilverLight多个页面、控件中传递回调方法

    在论坛中看到经常有人碰到如何在SilverLight多个页面或者控件中传替参数或者值的问题，今天抽空通过Delegate机制实现回调实例方法重设动画参数的DEMO,分享给大家。最终结果如图:

    演示地址:http://xingjunli.webs.com/DelegateDemo.html
    参考资料:动画概述：http://msdn.microsoft.com/zh-cn/library/cc189019(VS.95).aspx 委托：http://msdn.microsoft.com/zh-cn/library/900fyy8e.aspx
   1、初识委托:
      委托delegate有点类似于非托管C/C++中的函数指针，在C#中通过委托机制来回掉实例方法，静态方法等（更重要是委托为托管代码，能保证回调方法的类型的安全）
   2、使用委托回调实例方法:  
      2.1、用C#的delegate关键字来定义回掉函数的签名(本示例中我们通过一个单独的类来实义委托以提高重用):
 /// <summary> /// 声明delegate<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a> /// </summary> /// <p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m name="x"></p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m> /// <p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m name="y"></p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m> public delegate void delgateResetParentMethod(double x,double y);  
     2.2、在子窗体类中我们定义一个委托类型对象如:
 public helper.delgateResetParentMethod CallBackMethod; 
     2.3、在父窗体中实例化子窗体时将实例方法传递给委托:
  UCDelegateChildWindow childWindow = new UCDelegateChildWindow(); childWindow.CallBackMethod = ReaplayAnimation;

     2.4、用我们熟悉的方法调用语法来调用回掉函数:
if (this.DialogResult.Value && CallBackMethod != null) { this.CallBackMethod(Double.Parse(txtX.Text),Double.Parse(txtY.Text)); this.Close(); }

     3、上面我们应用委托实现了最简单的应用，实际工作中会复杂的多；我们的编译器和CLR为我们做了大量幕后工作以减轻使用的复杂性;如需了解更多请参考:委托（C# 编程指南）http://msdn.microsoft.com/zh-cn/library/ms173171.aspx
   实现步骤(附源代码):
     声明委托类型：

public class helper { /// <summary> /// 声明delegate<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a> /// </summary> /// <p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m name="x"></p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m> /// <p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m name="y"></p<a href="/tag/ara/" target="_blank" class="keywords">ara</a>m> public delegate void delgateResetParentMethod(double x,double y); } 
    子窗体XAML：

<controls:ChildWindow x:Class="LoadSilverlight.UCDelegateChildWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:controls="clr-namespace:Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Controls;assembly=Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Controls" Width="200" Height="170" Title="重设动画坐标:"> <Grid x:Name="LayoutRoot" Margin="2"> <Grid.RowDe<a href="/tag/Finitio/" target="_blank" class="keywords">Finitio</a>ns> <RowDe<a href="/tag/Finitio/" target="_blank" class="keywords">Finitio</a>n /> <RowDe<a href="/tag/Finitio/" target="_blank" class="keywords">Finitio</a>n Height="Auto" /> </Grid.RowDe<a href="/tag/Finitio/" target="_blank" class="keywords">Finitio</a>ns> <Canvas Grid.Row="0" Grid.Column="0" Margin="1"> <Canvas.Background> <LinearGradientB<a href="/tag/rush/" target="_blank" class="keywords">rush</a> EndPoint="0.5,1" StartPoint="0.5,0"> <GradientStop Color="#E6E0F3F4" Offset="0"/> <GradientStop Color="#FFB3BDC7" Offset="1"/> </LinearGradientB<a href="/tag/rush/" target="_blank" class="keywords">rush</a>> </Canvas.Background> <TextBlock Text="X:" Canvas.Left="11" Canvas.Top="8" /> <Text<a href="/tag/Box/" target="_blank" class="keywords">Box</a> x:Name="txtX" Canvas.Left="28" Canvas.Top="8" Width="140" Text="100" /> <TextBlock Text="Y:" Canvas.Left="12" Canvas.Top="46" RenderTransformOrigin="0.417,1.375" /> <Text<a href="/tag/Box/" target="_blank" class="keywords">Box</a> x:Name="txtY" Canvas.Left="28" Canvas.Top="44" Width="140" Text="100"/> </Canvas> <Button x:Name="CancelButton" Content="Cancel" Click="CancelButton_Click" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,12,0" Grid.Row="1" /> <Button x:Name="OKButton" Content="OK" Click="OKButton_Click" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,79,0" Grid.Row="1" /> </Grid> </controls:ChildWindow> 
    子窗体CS:

using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Collections.Generic; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Linq; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Net; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Controls; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Documents; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Input; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Media; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Media.Animation; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Shapes; namespace LoadSilverlight { public partial class UCDelegateChildWindow : ChildWindow { public UCDelegateChildWindow() { InitializeComponent(); } private void OKButton_Click(object sender,RoutedEventArgs e) { this.DialogResult = true; if (this.DialogResult.Value && CallBackMethod != null) { this.CallBackMethod(Double.Parse(txtX.Text),Double.Parse(txtY.Text)); this.Close(); } } private void CancelButton_Click(object sender,RoutedEventArgs e) { this.DialogResult = false; } //定义<a href="/tag/yemian/" target="_blank" class="keywords">页面</a>委托对象 public helper.delgateResetParentMethod CallBackMethod; } }  
    父窗体XAML:

<UserControl x:Class="LoadSilverlight.UCDelegateParent" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Background="#FF333333" Foreground="{x:Null}"> <UserControl.Resources> <Storyboard x:Name="sbRun"> <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.X)"> <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0"/> <EasingDoubleKeyFrame KeyTime="00:00:06" Value="200"> <EasingDoubleKeyFrame.EasingFunction> <ElasticEase EasingMode="Ea<a href="/tag/SEO/" title="SEO">SEO</a>ut"/> </EasingDoubleKeyFrame.EasingFunction> </EasingDoubleKeyFrame> </DoubleAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.Y)"> <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0"/> <EasingDoubleKeyFrame KeyTime="00:00:06" Value="200"> <EasingDoubleKeyFrame.EasingFunction> <ElasticEase EasingMode="Ea<a href="/tag/SEO/" title="SEO">SEO</a>ut"/> </EasingDoubleKeyFrame.EasingFunction> </EasingDoubleKeyFrame> </DoubleAnimationUsingKeyFrames> </Storyboard> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="#FF424242"> <Ellipse x:Name="ellipse" Height="64" HorizontalAlignment="Left" Margin="25,32,0" VerticalAlignment="Top" Width="64" RenderTransformOrigin="0.5,0.5"> <Ellipse.RenderTransform> <TransformGroup> <ScaleTransform/> <SkewTransform/> <RotateTransform/> <TranslateTransform x:Name="ellipseTrans"/> </TransformGroup> </Ellipse.RenderTransform> <Ellipse.Fill> <RadialGradientB<a href="/tag/rush/" target="_blank" class="keywords">rush</a> RadiusX="0.559" RadiusY="0.559"> <GradientStop Color="#FFFF0606"/> <GradientStop Color="#72702525" Offset="0.717"/> <GradientStop Color="#00702525" Offset="1"/> </RadialGradientB<a href="/tag/rush/" target="_blank" class="keywords">rush</a>> </Ellipse.Fill> </Ellipse> <Button x:Name="btnReset" Height="33" HorizontalAlignment="Right" Margin="0,8,8" VerticalAlignment="B<a href="/tag/ott/" target="_blank" class="keywords">ott</a>om" Width="100" Content="重设坐标" FontFamily="微软雅黑" FontWeight="Bold" FontSize="18.667"/> <HyperlinkButton HorizontalAlignment="Right" Margin="8,116,15" VerticalAlignment="B<a href="/tag/ott/" target="_blank" class="keywords">ott</a>om" Content="http://Blog.csdn.net/xingjunli" NavigateUri="http://Blog.csdn.net/xingjunli" FontStyle="Italic"/> </Grid> </UserControl>  
    父窗体CS:

using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Collections.Generic; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Linq; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Net; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Controls; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Documents; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Input; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Media; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Media.Animation; using Sy<a href="/tag/stem/" target="_blank" class="keywords">stem</a>.Windows.Shapes; namespace LoadSilverlight { public partial class UCDelegateParent : UserControl { UCDelegateChildWindow childWindow; public UCDelegateParent() { InitializeComponent(); btnReset.Click += new RoutedEventHandler(btnReset_Click); sbRun.Completed += new EventHandler(sbRun_Completed); this.Loaded += new RoutedEventHandler(UCDelegateParent_Loaded); } void UCDelegateParent_Loaded(object sender,RoutedEventArgs e) { sbRun.Begin(); } void sbRun_Completed(object sender,EventArgs e) { ShowChildWindow(); } void btnReset_Click(object sender,RoutedEventArgs e) { ShowChildWindow(); } private void ShowChildWindow() { if (childWindow == null) { childWindow = new UCDelegateChildWindow(); childWindow.CallBackMethod = ReaplayAnimation; //为子窗体(可以是任意窗体或者控件)<a href="/tag/zhuce/" target="_blank" class="keywords">注册</a>父窗体实例<a href="/tag/fangfa/" target="_blank" class="keywords">方法</a>(这里的参数类型和个数必须匹配) } childWindow.Show(); } //父窗体重设动画<a href="/tag/shuxing/" target="_blank" class="keywords">属性</a>播放动画 private void ReaplayAnimation(double x,double y) { DoubleAnimationUsingKeyFrames framsX = sbRun.Children[0] as DoubleAnimationUsingKeyFrames; DoubleAnimationUsingKeyFrames framsY = sbRun.Children[1] as DoubleAnimationUsingKeyFrames; framsX.KeyFrames[0].Value = framsX.KeyFrames[1].Value; framsX.KeyFrames[1].Value = x; framsY.KeyFrames[0].Value = framsY.KeyFrames[1].Value; framsY.KeyFrames[1].Value = y; sbRun.Stop(); sbRun.Begin(); } } }  
  结束语:SilverLight同.Net FrameWork本身已经很好的结合起来，C#中一些实用的编程机制(如：委托)，在SL中合理运用，将给我们带来意想不到的收获!