【求助各位大神】image字段如何还原成文件（已知文件格式）？
//判断是否有行选中
  if (DgvData.CurrentRow == null)
  {
  return;
  }

  //记录选中行
  DataGridViewRow row = DgvData.CurrentRow;


  SaveFileDialog saveFileDialog = new SaveFileDialog();

  //默认保存到E盘
  saveFileDialog.InitialDirectory = "E:\\";

  saveFileDialog.FileName = row.Cells["文件名"].Value.ToString();
  saveFileDialog.Filter = "Files(*." + row.Cells["扩展名"].Value.ToString()+")|*." + row.Cells["扩展名"].Value.ToString();

  DialogResult drResult = saveFileDialog.ShowDialog();


  //判断是否按下确定
  if (drResult != DialogResult.OK)
  { 
  return;
  }

  //连接数据库
  string sConnection = "Server = WIN-1JUUPA83A27\\SQL2005; DataBase = DataManagement; User ID = sa; Password = sa;";
  SqlConnection sqlCon = new SqlConnection(sConnection);
  sqlCon.Open();

  string sSelect = "select 保存的文件 from FileInformation where 文件名 = '" + row.Cells["文件名"].Value.ToString() +"'";
  SqlCommand sqlCmd = new SqlCommand(sSelect, sqlCon);

  MemoryStream ms = new MemoryStream();
  IFormatter formatter = new BinaryFormatter();
  formatter.Serialize(ms, sqlCmd.ExecuteScalar());

  // 把 Stream 转换成 byte[] 
  byte[] bytes = new byte[ms.Length];
  ms.Read(bytes, 0, bytes.Length);
  // 设置当前流的位置为流的开始 
  ms.Seek(0, SeekOrigin.Begin);

  // 把 byte[] 写入文件 
  FileStream fs = new FileStream(saveFileDialog.FileName, FileMode.Create);
  BinaryWriter bw = new BinaryWriter(fs);
  bw.Write(bytes);
  bw.Close();
  fs.Close();
  sqlCon.Close();

------解决方案--------------------
举个例子
File.WriteAllBytes(@"C:\a.jpg", bytes);