Silverlight.WebClient下载

System.Net.WebClient 是我们在客户端常用下载对象,image也是sl中出镜率较高的控件
再加上一个MediaElement控件,让我们就此实现一个会动的silverlightLOGO吧~


xaml的组成很简单:

<UserControl x:Class="SilverlightApplication1.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Width="400" Height="300">
    <Canvas Background="White">
        <MediaElement Width="50" Height="50" AutoPlay="True" x:Name="myMp"/>
        <Image x:Name="myImage" Width="150" Height="50" Canvas.Left="60" ></Image>
    </Canvas>
</UserControl>

接下来我们将 Image绑定图片:

new BitmapImage(new Uri("Properties/microsoft_silverlight_c - Copy.jpg", UriKind.Relative));

随后声明WebClient对象和注册委托事件:
webClient.openReadAsync()方法参数
1.位于服务器上的数据源的路径.
2.给与用户一个标识对本次访问服务器.

WebClient wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
wc.OpenReadAsync(new Uri("SilverlightLogo.zip", UriKind.Relative), "SilverlightLogo.wmv");

       void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
       {
           //读取数据完成
       }

当下载数据完成后回调openreadcompleted方法

我们可以从参数e中得到有用的数据

String sURI = e.UserState as String;
StreamResourceInfo zipResourceInfo = new StreamResourceInfo(e.Result as Stream, null);
StreamResourceInfo imageResourceInfo = Application.GetResourceStream(zipResourceInfo, new Uri(sURI, UriKind.RelativeOrAbsolute));
myMp.SetSource(imageResourceInfo.Stream);

就这样我们已将一个会动的silverlightlogo展现给用户了,很简单吧~

Source code: download.