Silverlight中WebClient下载资源

首先新建一个Silverlight应用程序带Web的，在Web程序中放入一个txt文件，名为TextFile1.txt。内容Silverlight is very good!

然后在silverlight项目中添加一个silverlight user control名为WebClientDownResource.xaml

xaml的内容为：

<Grid x:Name="LayoutRoot" Background="White">

        <Grid.ColumnDefinitions>

            <ColumnDefinition>

            </ColumnDefinition>

        </Grid.ColumnDefinitions>

        <Grid.RowDefinitions>

            <RowDefinition Height="Auto">

            </RowDefinition>

            <RowDefinition Height="auto">

            </RowDefinition>

            <RowDefinition Height="auto" >

            </RowDefinition>

        </Grid.RowDefinitions>

        

        <Button Grid.Row="1" Grid.Column="0" Content="DownText" Height="23" HorizontalAlignment="Left"  Name="Down" VerticalAlignment="Top" Width="75" Margin="12,0,0,0" Click="Down_Click" />

        <TextBlock  Grid.Row="0" Grid.Column="0" Height="23" HorizontalAlignment="Left" Margin="10,10,0,0" Name="textBlock1" Text="TextBlock" VerticalAlignment="Top" Width="350" />

        <ProgressBar Grid.Row="2" Grid.Column="0" Height="10" HorizontalAlignment="Left" Margin="10,10,0,0" Name="progressBar1" VerticalAlignment="Top" Width="100" />

    </Grid> 

后台的代码：

private void Down_Click(object sender, RoutedEventArgs e)

        {

            string uri = Application.Current.Host.Source.AbsoluteUri;

            int index = uri.IndexOf("/ClientBin");

            uri = uri.Substring(0, index) + "/TextFile1.txt";



            WebClient webClient = new WebClient();

            webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);

            webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(webClient_DownloadProgressChanged);

            webClient.OpenReadAsync(new Uri(uri));

        }



        void webClient_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)

        {

            this.progressBar1.Value = e.ProgressPercentage;

        }

        private void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)

        {

            if (e.Error != null)

            {

                // (Add code to display error or degrade gracefully.)

            }

            else

            {

                Stream stream = e.Result;

               StreamReader reader=new StreamReader(stream);

                this.textBlock1.Text=reader.ReadToEnd();

                reader.Close();

            }

        } 

具体的关于webclient的内容可以参考《pro silverlight 4 in c#》中的第6章内容。