请问如何把数据库的图片（二进制文件）导到本地文件夹

Question

/// <summary>
        /// 通过ID得到图片的MemoryStream，可以直接显示在图片框里
        /// </summary>
        /// <returns></returns>
        public static MemoryStream ID2FileStream(int id)
        {
            MemoryStream rtn = null;            try
            {
                string strSQL = "select filedata from t_filebase where id = " + id.ToString();                SqlConnection db = new SqlConnection(strConn);
                db.Open();
                SqlCommand cmd = new SqlCommand(strSQL, db);
                SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SequentialAccess);                if (!reader.Read())
                {
                    rtn = null;
                }
                else
                {                    Byte[] byteBLOBData = new Byte[0];
                    byteBLOBData = (Byte[])(reader["FileData"]);
                    MemoryStream stmBLOBData = new MemoryStream(byteBLOBData);
                    rtn = stmBLOBData;
                }                reader.Close();
                cmd.Dispose();
                db.Close();
                db.Dispose();                return rtn;
            }
            catch
            {
                return null;
            }
        }        /// <summary>
        /// ID -> File
        /// </summary>
        /// <param name="id"></param>
        /// <param name="file"></param>
        /// <returns></returns>
        public static bool ID2File(int id,string file)
        {
            bool rtn = false;            try
            {
                FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write);                MemoryStream ms = new MemoryStream();
                ms = ID2FileStream(id);                if (ms == null)
                {
                    rtn = false;
                }
                else
                {                    byte[] data = new byte[ms.Length];                    ms.Read(data, 0, data.Length);                    fs.Write(data, 0, (int)data.Length);
                    fs.Close();                    rtn = true;
                }                ms.Close();
                ms.Dispose();
            }
            catch
            {
                rtn = false;
            }
            return rtn;
        }

Answer 1

...
dbdatareader rd...
object obj=rd.getvalue(图象列);
if (obj == null)
  return new byte[0];
else
  try
  {
                byte[] buffer = (byte[])obj;
                return buffer;
            }
  catch (Exception)
            {
                return new byte[0];
            }
其中buffer就是图象