conn = new SqlConnection(connectionString.Text);
                SQL_MHT_SELECT = new SqlCommand("SELECT mht FROM documents WHERE id=" + s, conn); 
                string fileName = Application.StartupPath + @"\Temp\" + s + ".mht";
                FileStream filestream = File.Open(fileName, FileMode.Create, FileAccess.Write);
                if (filestream != null)
                {
                    //Создаем объект streamwriter и связываем его с потоком filestream
                    StreamWriter streamwriter = new StreamWriter(filestream);
                    BinaryWriter bw = new BinaryWriter(filestream);
                    int bufferSize =  20000000 ;
                    byte[] buffer = new byte[bufferSize];
                    long startIndex =  0 ;
                    int columnIdx =  0 ;
                    //bool doc_null = false;
                    try
                    {
                        conn.Open();
                        myReader = SQL_MHT_SELECT.ExecuteReader();
                        myReader.Read();

                        long retval = myReader.GetBytes(columnIdx, startIndex, buffer,  0 , bufferSize);
                        while (retval == bufferSize)
                        {
                            bw.Write(buffer);
                            bw.Flush();

                            startIndex += bufferSize;
                            retval = myReader.GetBytes(columnIdx, startIndex, buffer,  0 , bufferSize);
                        }
                        bw.Write(buffer,  0 , (int)retval);
                        bw.Flush();

                        streamwriter.Write(buffer);
                        //Переносим данные из потока в файл
                        streamwriter.Flush();
                        streamwriter.Close();
                        conn.Close();
                    }
                    catch (Exception excp) { conn.Close(); MessageBox.Show("ERROR: " + excp.ToString()); }

                }