SL4.图片下载进度条

XAML：

        <Canvas> 
            <Image Name="image" ></Image>
            <ProgressBar Name="progressbar" Width="270" Height="40" Canvas.Left="37" Canvas.Top="212"></ProgressBar>
            <Button Canvas.Left="94" Canvas.Top="316" Content="Button" Height="23" Name="button1" Width="75" Click="button1_Click" />
        </Canvas>

　　

XAML.CS:

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            this.progressbar.Value = 0;
            Uri uri = new Uri("Images/MyLogo.jpg", UriKind.RelativeOrAbsolute);
            BitmapImage bitmap = new BitmapImage();
            bitmap.DownloadProgress += new EventHandler<DownloadProgressEventArgs>(bitmap_DownloadProgress);
            bitmap.UriSource = uri;
            image.Source = bitmap;
        }
        void bitmap_DownloadProgress(object sender,DownloadProgressEventArgs e )
        {
            progressbar.Value = (double)e.Progress;
        }