ขอความช่วยเหลือเรื่อง การอ่าน file จาก database โดยใช้ filestream ของ sql server

 private void simpleButton2_Click(object sender, EventArgs e)
        {
            using (TransactionScope transactionScope2 = new TransactionScope())
            {
                SqlConnection sqlConnection3 = new SqlConnection("Data Source= DARKEDITION ;Initial Catalog=FileSystemDB;User Id = sa ;Password=123456;Integrated Security=True");
                SqlCommand sqlCommand3 = sqlConnection3.CreateCommand();
                sqlCommand3.CommandText = "Select FileData.PathName() As Path, GET_FILESTREAM_TRANSACTION_CONTEXT() As TransactionContext From PictureTable Where PkId = (Select Max(PkId) From PictureTable)";
                sqlConnection3.Open();
                SqlDataReader reader = sqlCommand3.ExecuteReader();
                reader.Read();
                string filePath = (string)reader["Path"];
                byte[] transactionContext2 = (byte[])reader["TransactionContext"];
                SqlFileStream sqlFileStream2 = new SqlFileStream
                    (filePath, transactionContext2, FileAccess.Read);
                byte[] buffer = new byte[(int)sqlFileStream2.Length];
                string FilePath = Application.StartupPath+ @"\QERP" ;
                sqlFileStream2.Read(buffer, 0, buffer.Length);
                File.WriteAllBytes(FilePath, buffer);
                sqlFileStream2.Close();
                ProcessStartInfo info = new ProcessStartInfo(FilePath);
                Process Proc = Process.Start(FilePath);
                Proc.WaitForExit();
                File.Delete(FilePath);
                transactionScope2.Complete();
            }
        }