以檔案系統的方式存取 Isolated Storage中的檔案
Silverlight For Windows Phone 提供了相同的儲存的架構 “獨立的儲存體”(Isolated Storage), 它會將資料儲存在獨立的實體記憶單元中，並且也獨立(Isolated)於每個應用程式，意思是說
“每個應用程式只能夠存取自己產生的資料，而其他的應用程式產生的資料是無法(也不知道)存取的”, 舉個例子: 一個記事本應用程式，無法開啟另一個程式(MP3播放器產生的mp3清單資料
如果程式移除後，因為該資料屬於程除的程式，所以也會一併的從系統中移除，怎麼備份 ~~ 目前好像只有藉由雲端(Cloud)進行備份。
我們以檔案系統的方式存取 Isolated Storage 需要使用 IsolatedStorageFile 類別來存取資料
IsolatedStorageFile 類別，在 namespace System.IO.IsolatedStorage
片段程式:
儲存資料:
1: try
2: {
3: using (var isostorage = IsolatedStorageFile.GetUserStoreForApplication())
4: using (var filestream = new IsolatedStorageFileStream("TestFile.Txt",
5: FileMode.Create,
6: FileAccess.Write,
7: isostorage))
8: {
9: StreamWriter SWriter = new StreamWriter(filestream);
10: writer.Write("This is TestFile Content ");
11: writer.Close();
12: }
13: }
14: catch (Exception)
15: {
16: MessageBox.Show("Save Fail");
17: }
讀取資料:
1: string filename ;
2: string fileContent ;
3: try
4: {
5: using (var isostorage = System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
6: using (var filestream= new solatedStorageFileStreamfilename,
7: FileMode.Open,
8: FileAccess.ReadWrite, isostorage))
9: {
10: StreamReader sreader = new StreamReader(stream);
11: fileContent = reader.ReadToEnd();
12: filename = filename;
13: reader.Close(); } }catch(Exception)
14: {
15: MessageBox.Show("Load Fail");
16: }
針對參數補充(參考自 Microsoft MSDN)
a. FileMode
Specifies how the operating system should open a file.
Namespace: System.IO
| CreateNew | Specifies that the operating system should create a new file.
|
| Create | Specifies that the operating system should create a new file. If the file already exists, it will be overwritten.
Create is equivalent to requesting that if the file does not exist, use CreateNew; otherwise, use Truncate |
| Open | Specifies that the operating system should open an existing file. The ability to open the file is dependent on the value specified
by FileAccess. A System.IO.FileNotFoundException is thrown if the file does not exist |
| OpenOrCreate | Specifies that the operating system should open a file if it exists; otherwise, a new file should be created |
| Truncate | Specifies that the operating system should open an existing file. Once opened, the file should be truncated so that its size is zero bytes. |
| Append | Opens the file if it exists and seeks to the end of the file, or creates a new file. Append can only be used in conjunction with Write.
Attempting to seek to a position before the end of the file will throw an IOException and any attempt to read fails and throws an NotSupportedException. |
b.FileAccess
Defines constants for read, write, or read/write access to a file.
Namespace: System.IO
| Read | Read access to the file. Data can be read from the file. Combine with Write for read/write access. |
| Write | Write access to the file. Data can be written to the file. Combine with Read for read/write access. |
| ReadWrite | Read and write access to the file. Data can be written to and read from the file. |