Silverlight实现星星闪烁动画

本文实例为大家分享了Silverlight实现星星闪烁动画展示的具体代码，供大家参考，具体内容如下

原理很简单，生成1000个圆，从随机数来布置它们的位置，通过动画来处理它们的透明度，动画时长也是随机生成。 

1、创建图形数组并设置背景透明，渐变笔触，大小等，而后加入到Grid元素的子元素集中；
2、创建动画时间线；
3、加载完成后播放动画；
4、每一轮动画播放完毕后，重新随机生成一下图形的Margin，动画的时间长度也是随机生成。

代码： 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes; 
 
namespace RandEllipseSample
{
  public partial class MainPage : UserControl
  {
    int shapesCount = 500; //图形数组的容量
    //随机大小的上限
    int theMaxW = 1300;
    int theMaxH = 720;
    Random rand = null;
    Storyboard story = null;
    Ellipse[] myShapes = null;
    public MainPage()
    {
      InitializeComponent();
      rand = new Random();
      story = new Storyboard();
      story.Completed += new EventHandler(story_Completed);
      InitShapes();
      InitAnimation();
      //加载完成后马上播放动画
      this.Loaded += new RoutedEventHandler(MainPage_Loaded);
    } 
 
    void MainPage_Loaded(object sender, RoutedEventArgs e)
    {
      story.Begin();
    } 
 
    void story_Completed(object sender, EventArgs e)
    {
      for (int x = 0; x < shapesCount; x++)
      {
 myShapes[x].Margin = new Thickness(Convert.ToDouble(rand.Next(0, theMaxW)), Convert.ToDouble(rand.Next(0, theMaxH)), 0, 0);
      }
      InitAnimation();
    } 
 
    /// 

    /// 初始化形状数组
    /// 
    private void InitShapes()
    {
      myShapes = new Ellipse[shapesCount];
      //实例化所有成员
      for (int n = 0; n < shapesCount; n++)
      {
 myShapes[n] = new Ellipse();
 myShapes[n].Fill = new SolidColorBrush(Colors.Transparent);
 myShapes[n].StrokeThickness = 2d;
 //笔触为线性渐变
 LinearGradientBrush gBrush = new LinearGradientBrush();
 gBrush.StartPoint = new Point(0, 0);
 gBrush.EndPoint = new Point(1, 1);
 gBrush.GradientStops.Add(new GradientStop()
 {
   Color = Colors.Yellow,
   Offset = 0
 });
 gBrush.GradientStops.Add(new GradientStop()
 {
   Color = Colors.Red,
   Offset = 0.25
 });
 gBrush.GradientStops.Add(new GradientStop()
 {
   Color = Colors.White,
   Offset = 0.5
 });
 gBrush.GradientStops.Add(new GradientStop()
 {
   Color = Colors.Blue,
   Offset = 0.75
 });
 myShapes[n].Stroke = gBrush;
 //位置
 myShapes[n].Margin = new Thickness(Convert.ToDouble(rand.Next(0,theMaxW)), Convert.ToDouble(rand.Next(0,theMaxH)), 0, 0);
 //大小
 myShapes[n].Width = 10;
 myShapes[n].Height = 10;
 myShapes[n].HorizontalAlignment = HorizontalAlignment.Left;
 myShapes[n].VerticalAlignment = VerticalAlignment.Top;
 //加入可视化树
 this.LayoutRoot.Children.Add(myShapes[n]);
      }
    } 
 
    /// 

    /// 初始化动画
    /// 
    private void InitAnimation()
    {
      story.Children.Clear();
      for (int i = 0; i < shapesCount; i++)
      {
 int mSecond = rand.Next(0, 5);
 //透明度
 DoubleAnimation opacityAnimate = new DoubleAnimation();
 opacityAnimate.From = 1.0;
 opacityAnimate.To = 0.0;
 Storyboard.SetTarget(opacityAnimate, myShapes[i]);
 Storyboard.SetTargetProperty(opacityAnimate,
   new PropertyPath("Opacity"));
 opacityAnimate.Duration = new Duration(TimeSpan.FromSeconds(mSecond));
 opacityAnimate.RepeatBehavior = RepeatBehavior.Forever; 
 
 //将时间线添加到情节摘要
 story.Children.Add(opacityAnimate);
      }
    }
  }
}

效果图：

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