獲得BLOB值

using System;
using System.Data;
using System.Data.SqlClient;
using System.IO;

class Sample
{
 public static void Main()
 {
  SqlConnection pubsConn = new SqlConnection("Data Source=diana//diana;Integrated Security=SSPI;Initial Catalog=pubs;");
  SqlCommand logoCMD = new SqlCommand("select pub_id,logo from pub_info",pubsConn);
  //保存blob文件
  FileStream fs;
  BinaryWriter bw;
  //緩衝區大小
  int bufferSize = 100;
  //緩衝區
  byte[] outbyte = new byte[bufferSize];
  long reval;
  long startIndex = 0;
  string pub_id = "";
  //打開鏈接
  pubsConn.Open();
  SqlDataReader myReader = logoCMD.ExecuteReader(CommandBehavior.SequentialAccess);
  while(myReader.Read())
  {
   //獲得出版商id，必須在讀取blob列之前獲取
   pub_id = myReader.GetString(0);
   //創建輸出文件
   fs = new FileStream("logo" + pub_id + ".bmp",FileMode.OpenOrCreate,FileAccess.Write);
   bw = new BinaryWriter(fs);
   //重置起始位置
   startIndex = 0;
   //第一次讀取blob到緩衝區
   retval = myReader.GetBytes(1,startIndex,outbyte,0,bufferSize);
   //讀完爲止
   while(retval == bufferSize)
   {
    bw.Write(outbyte);
    bw.Flush();
    //重定位
    startIndex += bufferSize;
    retval = myReader.GetBytes(1,startIndex,outbyte,0,bufferSize);
   }
   //最後把不足緩衝區大小的緩衝區寫入文件
   bw.Write(outbyte);
   bw.Flush();
   //關閉輸出文件
   bw.Close();
   fs.Close();
  }
  //關閉讀取器和鏈接
  myReader.Close();
  pubsConn.Close();
 }
}