Question

I get the following on the second using(StreamWriter statement:

Value does not fall within the expected range.

            #region save allowance
            IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();

            //Open existing file
            IsolatedStorageFileStream fileStream = myIsolatedStorage.OpenFile("foo.txt", FileMode.Truncate, FileAccess.Write);
            using (StreamWriter writer = new StreamWriter(fileStream))
            {
                writer.Write(App.ViewModel.Foo);
            }
            #endregion

            #region save log

            IsolatedStorageFileStream fileStream2 = myIsolatedStorage.OpenFile("log.txt", FileMode.Truncate, FileAccess.Write);
            using (StreamWriter writer = new StreamWriter(fileStream))
            {
                foreach( var i in App.ViewModel.Items )
                    writer.Write(i.ToString());
            }

            #endregion

Answer 1

You’re reusing fileStream the second time instead of fileStream2. By the way, to avoid this kind of mistake, you may want to wrap your filestream inside the using block.

        #region save allowance
        IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();

        //Open existing file
        using (var writer = new StreamWriter(myIsolatedStorage.OpenFile("foo.txt", FileMode.Truncate, FileAccess.Write)))
        {
            writer.Write(App.ViewModel.Foo);
        }
        #endregion

        #region save log

        using (var writer = new StreamWriter(myIsolatedStorage.OpenFile("log.txt", FileMode.Truncate, FileAccess.Write)))
        {
            foreach( var i in App.ViewModel.Items )
                writer.Write(i.ToString());
        }

        #endregion