Silverlight为什么要使用程序扩展服务

2010-08-08 21:41 撞破南墙阅读(1620) 评论(0) 编辑收藏举报

应用程序扩展服务是什么？为什么要使用？一开始看的时候我也很疑惑。于是Google了一下。

BTW:baidu似乎不够用...

Sometimes working with silverlight you need to have a sort of service, always available for global tasks or

working in background notifing the main thread when something happen.

-------Andrea Boschin

具体用法：

1首先继承实现一个每7秒就报时来模拟一个读取新闻或者其他定时处理之类的东西

代码


    /// <summary>
    /// 每7秒钟报一次时间
    /// </summary>
    public class ASvc : IApplicationService {
        /// <summary>
        /// 自己 单例模式
        /// </summary>
        public static ASvc Current { get; set; }
        public event EventHandler timeOver;
        void dis_Tick(object sender, EventArgs e) {
            timeOver(sender, e);
        }
        public ASvc() {
            Current = this;
        }

        #region IApplicationService Members

        private DispatcherTimer dis;
        public void StartService(ApplicationServiceContext context) {
            MessageBox.Show("StartService" + context.ApplicationInitParams);
            dis = new DispatcherTimer();
            dis.Interval = TimeSpan.FromSeconds(7);
            dis.Tick += new EventHandler(dis_Tick);
            dis.Start();
        }
        public void StopService() {
            MessageBox.Show("StopService");
            dis.Stop();
            dis.Tick -= dis_Tick;
        }
        #endregion
    }

2注册

<Application xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
             x:Class="SLstudy.App"
               xmlns:svc="clr-namespace:SLstudy"
             >
    <Application.ApplicationLifetimeObjects>
        <svc:ASvc/>
    </Application.ApplicationLifetimeObjects>
    <Application.Resources>

    </Application.Resources>
</Application>

或者在代码中添加

    public App() {
          this.ApplicationLifetimeObjects.Add(new ASvc());
}

3调用

代码

   ASvc.Current.timeOver += new System.EventHandler(aSvc_timeOver);
        }

        void aSvc_timeOver(object sender, System.EventArgs e) {
            MessageBox.Show(sender + "7秒钟啦");
        }