Windows Phone 7 和 WCF 视频服务

Question

我正在尝试实现一项服务，该服务将允许用户从 Windows Phone 7 客户端（类似于 youtube）观看视频并将视频上传到 WCF 服务。现在，我有了将视频文件 (.wmv) 发送到客户端的服务的基本实现，该客户端具有 Silverlight 框架的 MediaElement 实现（与同一类的 .NET 实现有一些差异）。现在，每当我尝试在客户端本地播放视频时，都会收到 SecurityException is unhandled 错误。当我尝试将服务调用封装在 try/catch 块中时，应用程序就挂在那里。 代码如下：

服务器端：

 class TransferService: ITransferService
    {
        public FileStream DownloadFile(string filename)
        {
            //string FilePath = Path.Combine(@"c:\Uploads", filename);

            FileStream result = File.Open(@"C:\Uploads\test.wmv", FileMode.Open, FileAccess.Read, FileShare.Read);
            return result;
        }

        public void UploadFile(FileStream request)
        {
            //Not yet implemented
        }
    }

服务器端（web.config）：

    <configuration>

    <system.web>
        <compilation debug="true" targetFramework="4.0" />
        <httpRuntime maxRequestLength="100240" />
    </system.web>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="basicHttp" allowCookies="true"
                 maxReceivedMessageSize="20000000"
                 maxBufferSize="20000000"
                 maxBufferPoolSize="20000000" transferMode="Buffered">
          <readerQuotas maxDepth="200000000"
                        maxArrayLength="200000000"
                        maxStringContentLength="200000000"
                        maxBytesPerRead="200000000"
                        maxNameTableCharCount="200000000"/>
        </binding>
      </basicHttpBinding>
    </bindings>

    <services>
      <service name="VideoService.TransferService" behaviorConfiguration="VideoServiceTypeBehaviors" >
        <endpoint contract="IMetadataExchange" binding="mexHttpBinding" address="mex" />
        <endpoint contract="VideoService.ITransferService" binding="basicHttpBinding" address="basic" />
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/"/>
          </baseAddresses>
        </host>
      </service>
    </services>

        <behaviors>
          <serviceBehaviors>
            <behavior name="VideoServiceTypeBehaviors" >
              <serviceMetadata httpGetEnabled="true" />
            </behavior>
          </serviceBehaviors>
        </behaviors>

  </system.serviceModel>
</configuration>

客户端：

    public partial class Page1 : PhoneApplicationPage
        {
            TransferServiceClient sc;
            public Page1()
            {
                InitializeComponent();
                sc = new TransferServiceClient();
                this.Loaded += new RoutedEventHandler(Page_Loaded);
            }
            void Page_Loaded(object sender, RoutedEventArgs e)
            {

                sc.DownloadFileCompleted += new EventHandler<DownloadFileCompletedEventArgs>(sc_DownloadFileCompleted); //I think the problem is here
                sc.DownloadFileAsync("test.wmv");
            }
void sc_DownloadFileCompleted(object sender, DownloadFileCompletedEventArgs e)
        {
            myMediaElement.SetSource(e.Result);
            myMediaElement.Play();
        }

客户端（ServiceReference.clientconfig）：

<configuration>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="BasicHttpBinding_ITransferService" closeTimeout="00:02:00"
          openTimeout="00:02:00" receiveTimeout="00:10:00" sendTimeout="00:02:00"
          maxBufferSize="210005536" maxReceivedMessageSize="210005536"
          textEncoding="utf-8">
          <security mode="None" />
        </binding>
        <binding name="BasicHttpBinding_ITransferService1" maxBufferSize="2147483647"
          maxReceivedMessageSize="2147483647">
          <security mode="None" />
        </binding>
      </basicHttpBinding>
    </bindings>
    <client>
      <endpoint address="http://localhost:53163/TransferService.svc/basic"
        binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_ITransferService1"
        contract="TransferService.ITransferService" name="BasicHttpBinding_ITransferService" />
    </client>
  </system.serviceModel>
</configuration>

任何帮助或见解将不胜感激。谢谢

Answer 1

首先我会尝试正确使用这个代码块：

sc.DownloadFileCompleted += new EventHandler(sc_DownloadFileCompleted); //我认为问题出在这里 sc.DownloadFileAsync("test.wmv"); myMediaElement.Play();

您启动了一个异步下载过程，并且您正在附加一个“下载完成”回调...... 为什么在异步调用之后同步调用“myMediaElement.Play”？ 此时，文件尚未下载，可能 mediaelement 触发了异常，因为文件被锁定（因为下载）。

您必须在异步下载过程完成后调用“sc_DownloadFileCompleted”-Handler 中的“myMediaElement”......

请检查这是不是问题...