將從Web服務接收的數據存儲在windows phone 7應用程序的隔離存儲中

Question

我正在爲windows phone 7構建一個應用程序，我需要從Web服務提取數據並將其顯示在我的應用程序中。現在每次調用Web服務數據的頁面都會被稱爲Web服務，並且一次又一次地調用Web服務，因此需要花費時間來顯示數據。因此，我想將數據存儲在獨立存儲中，以便每次都不會調用Web服務。請幫助我做到這一點。我的代碼調用Web服務的地址是：

public const string aboutxml = "about.xml"; 

    public about() 
    { 
     InitializeComponent(); 
     LoadData(); 
    } 

    private void LoadData() 
    { 
     bool isSuccess; 
     //try to load data from iso store 
     var doc = ReadXml(out isSuccess); 
     if (isSuccess) PopulateList(doc); 
     //if failed (data doesn't exists in iso store), download data from web service 
     else 
     { 
      KejriwalService.aapSoapClient myclient = new KejriwalService.aapSoapClient(); 
      myclient.getarvindAboutCompleted += new EventHandler<KejriwalService.getarvindAboutCompletedEventArgs>(myclient_getarvindAboutCompleted); 
      myclient.getarvindAboutAsync(); 
      progressName.Visibility = System.Windows.Visibility.Visible; 

     } 
    } 

    //upon download completed, display data then save the xml to iso store 
    void myclient_getarvindAboutCompleted(object sender, KejriwalService.getarvindAboutCompletedEventArgs e) 
    { 
     var doc = XDocument.Parse(e.Result); 
     PopulateList(doc); 
     WriteXml(doc); 
    } 


    private void PopulateList(XDocument doc) 
    { 
      var data = e.Result; 

     XElement xml = XElement.Parse(data); 

     aboutview.Text = xml.Elements("UserDetails").Elements("about_details").First().Value; 
     progressName.Visibility = System.Windows.Visibility.Collapsed; 

    } 

    private XDocument ReadXml(out bool isSuccess) 
    { 
     isSuccess = false; 
     var doc = new XDocument(); 
     using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) 
     { 
      try 
      { 
       if (store.FileExists(aboutxml)) 
       { 
        using (var sr = new StreamReader(new IsolatedStorageFileStream(aboutxml, FileMode.OpenOrCreate, store))) 
        { 
         doc = XDocument.Load(sr); 
        } 
        isSuccess = true; 
       } 
      } 
      catch (Exception ex) { } 
     } 
     return doc; 
    } 

    private bool WriteXml(XDocument document) 
    { 
     using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) 
     { 
      try 
      { 
       using (var sw = new StreamWriter(new IsolatedStorageFileStream(aboutxml, FileMode.Create, store))) 
       { 
        sw.Write(document.ToString()); 
       } 
      } 
      catch (Exception ex) { return false; } 
     } 
     return true; 
    } 

Answer 1

好吧，我很清楚你想要一些代碼，以便我們開始吧，試試下面的代碼：

public const string NewssXml = "Newss.xml"; 

public News() 
{ 
    InitializeComponent(); 
    LoadData(); 
} 

private void LoadData() 
{ 
    bool isSuccess; 
    //try to load data from iso store 
    var doc = ReadXml(out isSuccess); 
    if(isSuccess) PopulateList(doc); 
    //if failed (data doesn't exists in iso store), download data from web service 
    else 
    { 
     KejriwalService.aapSoapClient client = new KejriwalService.aapSoapClient(); 
     client.getarvindNewsCompleted += new EventHandler<KejriwalService.getarvindNewsCompletedEventArgs>(client_getarvindNewsCompleted); 
     client.getarvindNewsAsync(); 

     progressName.Visibility = System.Windows.Visibility.Visible; 
    } 
} 

//upon download completed, display data then save the xml to iso store 
void client_getarvindNewsCompleted(object sender, KejriwalService.getarvindNewsCompletedEventArgs e) 
{ 
    var doc = XDocument.Parse(e.Result); 
    PopulateList(doc); 
    WriteXml(doc); 
} 

private void PopulateList(XDocument doc) 
{ 
    List<Newss> listData = new List<Newss>(); 

    progressName.Visibility = System.Windows.Visibility.Collapsed; 

    foreach (var location in doc.Descendants("UserDetails")) 
    { 
     Newss data = new Newss(); 
     data.News_Title = location.Element("News_Title").Value; 
     data.News_Description = location.Element("News_Description").Value; 
     data.Date_Start = location.Element("Date_Start").Value; 
     data.image_path = location.Element("image_path").Value; 
     data.ImageBind = new BitmapImage(new Uri(@"http://political-leader.vzons.com/ArvindKejriwal/images/uploaded/"+data.image_path, UriKind.Absolute)); 
     listData.Add(data); 
    } 
    listBox1.ItemsSource = listData; 
} 

private XDocument ReadXml(out bool isSuccess) 
{ 
    isSuccess = false; 
    var doc = new XDocument(); 
    using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) 
    { 
     try 
     { 
      if (store.FileExists(NewssXml)) 
      { 
       using (var sr = new StreamReader(new IsolatedStorageFileStream(NewssXml, FileMode.OpenOrCreate, store))) 
       { 
        doc = XDocument.Load(sr); 
       } 
       isSuccess = true;    
      } 
     } catch (Exception ex) { } 
    } 
    return doc; 
} 

private bool WriteXml(XDocument document) 
{ 
    using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) 
    { 
     try 
     { 
      using (var sw = new StreamWriter(new IsolatedStorageFileStream(NewssXml, FileMode.Create, store))) 
      { 
       sw.Write(document.ToString()); 
      } 
     } catch (Exception ex) { return false; } 
    } 
    return true; 
} 

只有當你願意知道如何構建的：

• 一般步驟是和我上個月在this answer上解釋的一樣。從this blog post
• 適應
• ReadXml和WriteXml方法其餘部分從現有的代碼重構

Answer 2

將所有數據存儲在XDocument中並檢索開銷。而是使用您的數據庫來存儲和檢索數據。這會減少你的代碼工作。