Windows Phone 7：解密来自孤立存储的许多文件

Question

我正在尝试做一个程序，它在手机的独立存储内存中存储很多（5-15）.txt文件。我注意到使用Windows Phone Power Tools等程序来读取这些文件是多么容易，因此我决定对它们进行加密。我使用这个链接作为教程：

http://msdn.microsoft.com/en-us/library/windows/apps/hh487164(v=vs.105).aspx

加密正常工作，因为我明显节约一次一个文件。但是，我在尝试解密时遇到问题。 我应该如何编辑我的代码，以便解密很多.txt文件？下面是我的代码，我使用的时刻：

 private void IsoRead() 
    { 
     System.IO.IsolatedStorage.IsolatedStorageFile local = 
     System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication(); 

     string[] filenames = local.GetFileNames("./DataFolder/*.txt*"); 
     foreach (var fname in filenames) 
     { 
      //retrieve byte 
       byte[] ProtectedByte = this.DecryptByte(); 
      //decrypt with Unprotect method 
       byte[] FromByte = ProtectedData.Unprotect(ProtectedByte, null); 
      //convert from byte to string 
       fText = Encoding.UTF8.GetString(FromByte, 0, FromByte.Length); 

       this.Items.Add(new itemView() { LineOne = fname, LineTwo = fText }); 
     }   
    } 

而另外一个：

 private byte[] DecryptByte() 
    { 
     // Access the file in the application's isolated storage. 
     IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication(); 

     IsolatedStorageFileStream readstream = new IsolatedStorageFileStream 
      ("DataFolder\\"/*Here's where I'm having problems with*/, System.IO.FileMode.Open, FileAccess.Read, file); 

     // Read the written data from the file. 
     Stream reader = new StreamReader(readstream).BaseStream; 
     byte[] dataArray = new byte[reader.Length]; 
     reader.Read(dataArray, 0, dataArray.Length); 
     return dataArray; 

    } 

所以基本上程序有一个列表视图页面，得到的来自独立存储的文件。如果有人感动，它会进入一个新的页面，显示写入的内容。

奖金问题：我可以加密WP7/WP8中的文件夹吗？

编辑：在IsoRead中添加一行代码。

Answer 1

的XAML：

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> 
     <StackPanel> 
      <Button Content="Write Random File" Click="WriteFile" VerticalAlignment="Top" /> 
      <Button Content="Read files File" Click="ReadFiles" VerticalAlignment="Top" /> 
     </StackPanel> 
    </Grid> 

代码：

public partial class MainPage : PhoneApplicationPage 
{ 
    // Constructor 
    public MainPage() 
    { 
     InitializeComponent(); 
    } 

    private const string FilePath = "{0}.txt"; 

    private readonly List<ItemView> items = new List<ItemView>(); 

    private void WriteFile(object sender, RoutedEventArgs e) 
    { 
     var fileName = DateTime.Now.Ticks.ToString(CultureInfo.InvariantCulture); 

     // Convert text to bytes. 
     byte[] data = Encoding.UTF8.GetBytes(fileName); 

     // Encrypt byutes. 
     byte[] protectedBytes = ProtectedData.Protect(data, null); 

     // Store the encrypted bytes in iso storage. 
     this.WriteToFile(protectedBytes, fileName); 
    } 

    private void ReadFiles(object sender, RoutedEventArgs e) 
    { 
     items.Clear(); 

     using (var isoStore = IsolatedStorageFile.GetUserStoreForApplication()) 
     { 
      var files = isoStore.GetFileNames("*.txt"); 

      foreach (var file in files) 
      { 
       // Retrieve the protected bytes from isolated storage. 
       byte[] protectedBytes = this.ReadBytesFromFile(file); 

       // Decrypt the protected bytes by using the Unprotect method. 
       byte[] bytes = ProtectedData.Unprotect(protectedBytes, null); 

       // Convert the data from byte to string and display it in the text box. 
       items.Add(new ItemView { LineOne = file, LineTwo = Encoding.UTF8.GetString(bytes, 0, bytes.Length) }); 
      } 
     } 

     //Show all the data... 
     MessageBox.Show(string.Join(",", items.Select(i => i.LineTwo))); 
    } 

    private void WriteToFile(byte[] bytes, string fileName) 
    { 
     // Create a file in the application's isolated storage. 
     using (var file = IsolatedStorageFile.GetUserStoreForApplication()) 
     { 
      using (var writestream = new IsolatedStorageFileStream(string.Format(FilePath, fileName), System.IO.FileMode.Create, System.IO.FileAccess.Write, file)) 
      { 
       // Write data to the file. 
       using (var writer = new StreamWriter(writestream).BaseStream) 
       { 
        writer.Write(bytes, 0, bytes.Length); 
       } 
      } 
     } 
    } 

    private byte[] ReadBytesFromFile(string filePath) 
    { 
     // Access the file in the application's isolated storage. 
     using (var file = IsolatedStorageFile.GetUserStoreForApplication()) 
     { 
      using (var readstream = new IsolatedStorageFileStream(filePath, System.IO.FileMode.Open, FileAccess.Read, file)) 
      { 
       // Read the data in the file. 
       using (var reader = new StreamReader(readstream).BaseStream) 
       { 
        var ProtectedPinByte = new byte[reader.Length]; 

        reader.Read(ProtectedPinByte, 0, ProtectedPinByte.Length); 

        return ProtectedPinByte; 
       } 
      } 
     } 
    } 
} 

public class ItemView 
{ 
    public string LineOne { get; set; } 
    public string LineTwo { get; set; } 
}