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();
    } 
 
    /// <summary>
    /// 初始化形状数组
    /// </summary>
    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]);
      }
    } 
 
    /// <summary>
    /// 初始化动画
    /// </summary>
    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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