BITED-Windows8应用开发学习札记之三：如何在Win8应用中实现数据绑定

　　在微软官方提供的资源中，我们可以看到SampleDataSource.cs已经拥有了定义好了相应的数据结构以及实现类：

　　

　　建立本地数据

　　由于我们已经有数据以及相应的数据类，我们需要做的仅仅是将数据放进数据类中，并在数据源的构造函数中调用它：

　　首先定义一个方法，用来绑定本地数据：

 public SampleDataSource()
         {
             // Loca local data
             GetLocalFiles();
         }

　　为了使界面运行起来不影响效果，需要通过添加async关键字来进行操作。

　　其余解析均用注释的方式表示在代码中：

 public async Task GetLocalFiles()
         {
             string folderIndex = "Index_"; // Foler filter
             var Path = @"Data"; //Binding Folder

             var Folders = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFolderAsync(Path).GetResults().GetFoldersAsync();

             //对于每个folder分别取出
             foreach (var folder in Folders)
             {
                 var group = new SampleDataGroup(folder.Name, folder.Name, "", "", "");
                 var files = await folder.GetFilesAsync();

                 //对每个文件也需要分别取出
                 foreach (var file in files)
                 {
                     //判断文件类型是否为文本形式
                     if (!file.FileType.Equals(TXTFILEEXTENSION))
                     {
                         string filename = file.Name.Split(new char[] { '.' })[];

                         //判断文件名是否包括_index
                         if (filename.Contains(folderIndex))
                         {
                             group.SetImage("/" + Path + "/" + folder.Name + "/" + file.Name);
                         }
                         else
                         {
                             var pictureItem = new SampleDataItem(filename, filename, "",
                                 "/" + Path + "/" + folder.Name + "/" + file.Name, "", "", group);
                             group.Items.Add(pictureItem);
                         }
                     }
                 }

                 //文本情况的操作
                 foreach (var file in files)
                 {
                     if (file.FileType.Equals(TXTFILEEXTENSION))
                     {
                         string filename = file.Name.Split(new char[] { '.' })[];
                         if (filename.Contains("Index_"))
                         {
                             group.Description = await Windows.Storage.FileIO.ReadTextAsync(file);
                         }
                         else
                         {
                             var item = group.Items.First<SampleDataItem>(i => i.Title.Split(new char[] { '.' })[] == filename);
                             item.Description = item.Content = await Windows.Storage.FileIO.ReadTextAsync(file);
                         }
                     }
                 }
                 //最后把所有数据绑定到AllGroups中
                 _sampleDataSource.AllGroups.Add(group);
             }
         }

　　

　　

　　建立SKYDRIVE数据

　　首先，在SKYDRIVE中存入同名的文件，并在本地进行reference。同时需要注意的是：我们需要在网上下载一个LIVE SDK，具体操作如下：

1. 在  http://msdn.microsoft.com/en-US/live/ff621310 页面 下载Live SDK并安装。
2. 在你的工程里面引用此Live SDK。
3. 进入https://manage.dev.live.com/build?wa=wsignin1.0，配置你的项目可以调用SKYDRIVE SDK,注意在STEP3中，我们只有Package Name可以填入，其他两个可以忽视

　　然后写代码读取数据，并在构造函数中调用InitAuth()方法(请先将GetLocalFiles（）注释掉)

　　微软官网给出的代码修改如下：

         #region GetRemote Files
         private async void InitAuth()
         {
             if (!Windows.ApplicationModel.DesignMode.DesignModeEnabled)
             {
                 LiveAuthClient authClient = new LiveAuthClient();
                 LiveLoginResult authResult = await authClient.LoginAsync(new List<string>() { "wl.signin", "wl.skydrive" });
                 if (authResult.Status == LiveConnectSessionStatus.Connected)
                 {
                     App.Session = authResult.Session;
                 }
                 // Forece to logout then login
                 authClient.Logout();
                 authResult = await authClient.LoginAsync(new List<string>() { "wl.signin", "wl.skydrive" });
                 LoadProfile();
             }
         }

         private async void LoadProfile()
         {
             // We may use this code later, but comment them here.
             //LiveConnectClient client = new LiveConnectClient(App.Session);
             //LiveOperationResult liveOpResult = await client.GetAsync("me");
             //dynamic dynResult = liveOpResult.Result;
             //App.UserName = dynResult.name;
             LoadData();
         }

         public async void LoadData()
         {
             LiveConnectClient client = new LiveConnectClient(App.Session);

             LiveOperationResult albumOperationResult = await client.GetAsync("me/albums");
             dynamic albumResult = albumOperationResult.Result;
             foreach (dynamic album in albumResult.data)
             {
                 if (album.name == "TravelJourney")
                 {
                     LiveOperationResult travelJourneyOperationResult = await client.GetAsync(album.id + "/files");
                     dynamic travelJourneyResult = travelJourneyOperationResult.Result;
                     foreach (dynamic subalbum in travelJourneyResult.data)
                     {
                         var group = new SampleDataGroup(subalbum.id, subalbum.name, "", @"ms-appx:///Assets/DarkGray.png", subalbum.description);
                         LiveOperationResult pictureOperationResult = await client.GetAsync(subalbum.id + "/files");
                         dynamic pictureResult = pictureOperationResult.Result;

                         foreach (dynamic picture in pictureResult.data)
                         {
                             if (!picture.name.EndsWith(".txt"))
                             {
                                 if (picture.name.Contains("Index_"))
                                 {
                                     group.SetImage(picture.source);
                                 }
                                 else
                                 {
                                     var pictureItem = new SampleDataItem(picture.id, picture.name, "", picture.source, picture.description, picture.description, group);
                                     group.Items.Add(pictureItem);
                                 }
                             }
                         }

                         foreach (dynamic picture in pictureResult.data)
                         {
                             if (picture.name.EndsWith(".txt"))
                             {

                                 string filename = picture.name.Split(new char[] { '.' })[];
                                 StorageFile file = await DownLoadTxtFile(picture.id, picture.name);
                                 string description = await Windows.Storage.FileIO.ReadTextAsync(file);
                                 if (filename.Contains("Index_"))
                                 {
                                     group.Description = description;
                                 }
                                 else
                                 {
                                     var item = group.Items.First<SampleDataItem>(i => i.Title.Split(new char[] { '.' })[] == filename);
                                     item.Description = item.Content = description;
                                 }
                             }
                         }
                         this.AllGroups.Add(group);
                     }
                 }
             }
         }

         /// <summary>
         /// Simply check whether file exists.
         /// </summary>
         /// <param name="fileName"></param>
         /// <returns></returns>
         async Task<bool> DoesFileExistAsync(string fileName)
         {
             try
             {
                 await Windows.Storage.ApplicationData.Current.LocalFolder.GetFileAsync(fileName);
                 return true;
             }
             catch
             {
                 return false;
             }
         }

         /// <summary>
         /// Download file if description file does not exist.
         /// </summary>
         /// <param name="fileid"></param>
         /// <param name="filename"></param>
         /// <returns></returns>
         private async Task<StorageFile> DownLoadTxtFile(string fileid, string filename)
         {
             var fileExists = await DoesFileExistAsync(filename);
             if (fileExists)
             {
                 return await Windows.Storage.ApplicationData.Current.LocalFolder.GetFileAsync(filename);
             }
             else
             {
                 StorageFile file = await Windows.Storage.ApplicationData.Current.LocalFolder.CreateFileAsync(filename);
                 LiveConnectClient client = new LiveConnectClient(App.Session);
                 await client.BackgroundDownloadAsync(fileid + "/content", file);
                 return file;
             }
         }
         #endregion

　　本文部分内容BITED了解的也不是很深入。待进一步了解再给出更详细的经验解说。

　　

　　

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