Silverlight与HTML双向交互

　　Silverlight具备很好的用户体验，但有时需要在页面的布局上进行特殊处理，比如作为webpart集成到Sharepoint中等等。

　　HTML和Silverlight之间的双向交互可以更灵活的使用Silverlight进行开发，上午摸索了一下，记录在此。

　　一，向Silverlight传递数据，实现个性化加载

　　Silverlight在HTML中的引用是：

< object data = " data:application/x-silverlight-2, " type = " application/x-silverlight-2 " width = " 100% " height = " 100% " >
           < param name = " source " value = " ClientBin/VideoCenter.xap " />
           < param name = " onError " value = " onSilverlightError " />
           < param name = " background " value = " white " />
           < param name = " minRuntimeVersion " value = " 4.0.50401.0 " />
           < param name = " autoUpgrade " value = " true " />
                     < a href = " http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50401.0 " style = " text-decoration:none " >
               < img src = " http://go.microsoft.com/fwlink/?LinkId=161376 " alt = " Get Microsoft Silverlight " style = " border-style:none " />
           a >
object >

　　这种引用插件的方式提供了一系列的参数来实现个性加载，上面的代码中我们加了一行参数

< param name = " initParams " value = " CategoryId=1 " />

　　我们可以在Silverlight中处理这些参数，打开Silverlight应用程序的App代码文件，加上接收参数的代码

private void Application_Startup( object sender, StartupEventArgs e)
        {
             if (e.InitParams.Count ! = 0 )
            {
                foreach(var item in e.InitParams)
                {
                    this.Resources.Add(item.Key, item.Value);
                }
            }
            this.RootVisual = new MainPage();
        }

　　我们看到对e.InitParams的处理，即可得到了HTML中传进来的参数，实现个性化加载：

if (App.Current.Resources[ " CategoryId " ]! = null )
            {
                 int cateId = int .Parse(App.Current.Resources[ " CategoryId " ].ToString());
                CategoryItem c = new CategoryItem();
                c.CategoryID = cateId;
                this.gridOfList.Children.Add(c);
            }

　　二，Silverlight调用HTML中的脚本资源，实现自身的样式等修改

        首先我们可以在加载Silverlight组件的页面上编写一段Javascript脚本

function InvokePlayer(videoId) {
            document.getElementById( " divCategory " ).style.display = " none " ;
            var player = document.getElementById( " divPlayer " );
            player.style.width = " 100% " ;
            player.style.height = " 600px " ;
}

　　怎么在Silverlight中调用这个脚本呢?我们可以在某个事件中调用Silverlight提供的类方法

System.Windows.Browser.HtmlPage.Window.Invoke( " InvokePlayer " , videoId);

　　当然类似的方法还有几个：

(HtmlPage.Window.GetProperty( " InvokePlayer " ) as ScriptObject)InvokeSelf( " Good Function! " );HtmlPage.Window.Eval( " document.getElementById('result') " ) as HtmlElement…

　　即可实现调用脚本。经过以上的两个方法即可实现HTML和Silverlight之间双向传递数据的功能。