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Silverlight读取Zip文件中的图片与视频

  首先看看Demo的截图:

                      2 3 1

   下面我将一步步展示实现这个Demo的过程,这个需求就是读出Zip文件中的图片与视频。

    Demo整体架构:

                          捕获

   

    首先我们准备几张图片和视频,然后将其压缩至resource.zip文件中,做完之后,我们建立一个resource.xml文件记录压缩包内的资源

      <?xml version="1.0" encoding="utf-8" ?> 
      <files>
      <file type="video" name="a.wmv"/>
      <file type="image" name="1.jpg"/>
      <file type="image" name="2.jpg"/>
      <file type="image" name="3.jpg"/>
      <file type="image" name="4.jpg"/>
      </files>

    这个xml文件就记录了文件的类型和名称,完成之后我们将其压缩至resource.zip中(请注意:这一步对后面读取流会有影响)

    现在我们将UI设计好

         <Image x:Name="Image" />
         <MediaElement x:Name="Video" />
         <StackPanel HorizontalAlignment="Left" VerticalAlignment="Bottom" Opacity="0.5" Orientation="Horizontal" Margin="5,0,0,0" Name="stack">
            <Button Content="Prev" x:Name="PrevButton"  Height="30" Margin="0,0,5,0" Width="80" Opacity="1" Cursor="Hand" IsEnabled="False"  />
            <Button  x:Name="NextButton" Height="30" Margin="0,0,5,0" Width="80" Opacity="1" Content="Next" Cursor="Hand" IsEnabled="False"  />
         </StackPanel>

    在UI上放置了一个Image和MediaElement控件来显示读取的资源

    下面我们开始建立ResourceInfo.cs文件

       public enum ResourceType
      {
        Video,
        Image
      }
      public class ResourceInfo
      {
        public ResourceType Type
        {
            get;  set;
        }
        public string Name
        {
            get; set;
        }
       }

     文件的类型以枚举的形式表示,现在我们就在MainPage.xaml.cs中以WebClient完成数据的读取工作

     先声明3个类成员变量:

       private StreamResourceInfo zip;
       private List<ResourceInfo> resourceInfo;
       private int index = 0;

     现在我们就先获取流,其完整代码:

       public void Load(object sender,RoutedEventArgs e)
        {
            Uri uri = new Uri(HtmlPage.Document.DocumentUri, "resource.zip");
            WebClient webClient = new WebClient();
            webClient.OpenReadCompleted += (obj, args) => 
            {
                if (args.Error != null)
                {
                    return;
                }
                // 这几步将读出的流信息封装到reader中,这样便于后面使用Linq To Xml操作
                zip = new StreamResourceInfo(args.Result, null);
                StreamResourceInfo maininfo = Application.GetResourceStream(zip, new Uri("resource.xml", UriKind.Relative));
                StreamReader reader = new StreamReader(maininfo.Stream);
                XDocument doc = XDocument.Load(reader);
                var file = from c in doc.Descendants("file")
                           select new ResourceInfo
                           {
                               Type = (ResourceType)Enum.Parse(typeof(ResourceType), c.Attribute("type").Value, true),
                               Name = c.Attribute("name").Value
                           };
                resourceInfo = new List<ResourceInfo>();
                resourceInfo.AddRange(file);
                this.PrevButton.IsEnabled = true;
                this.NextButton.IsEnabled = true;
                Display(resourceInfo[0]);
            };
             webClient.OpenReadAsync(uri);
        }
         public void Display(ResourceInfo resource)
        {
            //获取相应的流数据
            StreamResourceInfo media = Application.GetResourceStream(zip,new Uri(resource.Name,UriKind.Relative));
            switch (resource.Type)
            {
                case ResourceType.Image:
                    Image.Visibility = Visibility.Visible;
                    Video.Visibility = Visibility.Collapsed;
                    BitmapImage image = new BitmapImage();
                    image.SetSource(media.Stream);
                    Image.Source = image;
                    break;
                case ResourceType.Video:
                    Image.Visibility = Visibility.Collapsed;
                    Video.Visibility = Visibility.Visible;
                    Video.SetSource(media.Stream);
                    Video.Play();
                    break;
            }
         }

          事实上加载这段代码后,我们已经可以将xml文件中标注的第一个资源a.wmv在页面进行成功的播放了

          我们继续界面上的Button实现的循环显示上一条,下一条资源功能

         private void StopVideo()
        {
            if (resourceInfo[index].Type == ResourceType.Video)
            {
                Video.Stop();
            }
        }
        private void PrevButton_Click(object sender, RoutedEventArgs e)
        {
            StopVideo();
            if (--index < 0)
            {
                index = resourceInfo.Count - 1;
            }
            Display(resourceInfo[index]);
        }
        private void NextButton_Click(object sender, RoutedEventArgs e)
        {
            StopVideo();
            if (++index >=resourceInfo.Count)
            {
                index = 0;
            }
            Display(resourceInfo[index]);
        }

         如此我们就完成了这个Demo