System.IO.IsolatedStorage メモ
using (var testStorage = IsolatedStorageFile.GetUserStoreForDomain()) using (var testFileStream = new IsolatedStorageFileStream("fuga.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite, testStorage)) using (var testFileWriter = new StreamWriter(testFileStream, Encoding.Default)) { testFileWriter.WriteLine("fuga"); }