用Windows Phone 7解析JSON對象

Question

我想從我創建的Uri中讀取並在windows phone 7應用上顯示它。 （我在做這個教程：http://msdn.microsoft.com/en-us/windowsmobile/Video/hh237494）。

我的問題是，該程序不進入OpenReadCompletedEventHandler，我不知道爲什麼。 （我把消息框爲了調試，我發現程序不會進入OpenReadCompletedEventHandler）。這裏是相關的代碼：

void myButton_Click(object sender, RoutedEventArgs e) 
    { 

     try 
     { 
      WebClient webClient = new WebClient(); 
      Uri uri = new Uri("http://localhost:44705/Service1.svc/GetAllBrands"); 
      webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted); 
      try 
      { 
       webClient.OpenWriteAsync(uri); 
       MessageBox.Show("opening sucsseded"); 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
     } 
     catch (Exception ex) 
     { 
      MessageBox.Show(ex.Message); 
     } 
    } 
    void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e) 
    { 
     MessageBox.Show("OpenRead Handler"); 

     // OpenWriteCompletedEventArgs temp = (OpenWriteCompletedEventArgs)e; 
     DataContractJsonSerializer serializer = null; 
     try 
     { 
      serializer = new DataContractJsonSerializer(typeof(ObservableCollection<Brand>)); 
      ObservableCollection<Brand> Brands = serializer.ReadObject(e.Result) as ObservableCollection<Brand>; 
      foreach (Brand b in Brands) 
      { 
       int id = b.BrandId; 
       string name = b.BrandName; 
       listBrands.Items.Add(id + "    " + name); 

      } 

     } 
     catch (Exception ex) 
     { 
      MessageBox.Show(ex.Message); 
     } 

    } 

在此先感謝！

Answer 1

我從來沒有使用過這一點，但快速谷歌帶我到這個頁面上MSDN - http://msdn.microsoft.com/en-us/library/system.net.webclient.openreadcompleted.aspx

這應該告訴你爲什麼它不工作 - 因爲你使用的是讀取事件寫入操作。您應該使用OpenWriteCompletedEventHandler與OpenWriteAsync按照MSDN上的此頁面 - http://msdn.microsoft.com/en-us/library/system.net.webclient.openwritecompleted.aspx