BLOB二进制字段读写，一致是一个十分麻烦的事情，本人在总结前人的基础，特对access,MDB数据库BLOB的读写总结如下：
using System.Data;using System.Data.OleDb;using System.Windows.Forms;using System.IO;namespace Book
...{
/**//// <summary> 
/// Db_Class 的摘要说明。
/// </summary> public class Db_Class ...{ private OleDbConnection Conn; private OleDbCommand cmd; //构造函数 public Db_Class(String MDBFileName, String Password) ...{ String Str = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Jet Oledb:Database Password={1}", MDBFileName, Password); Conn = new OleDbConnection(Str); //连接数据库,Password是MDB的密码 //by 闫磊 Email:Landgis@126.com,yanleigis@21cn.com 2007.10.13 } //打开数据源链接 public OleDbConnection Db_Conn() ...{ Conn.Open(); return Conn; } //返回DataReader数据集，下面的SQL可以动态生成 public OleDbDataReader Db_CreateReader(string SQL) ...{ try ...{ cmd = new OleDbCommand(SQL, Conn); OleDbDataReader Rs = cmd.ExecuteReader(); return Rs; } catch (Exception ex) ...{ MessageBox.Show("错误:因" + ex.Message + ",无法执行:" + SQL); return null; } } //返回DataReader数据集，下面的SQL是存储过程 public OleDbDataReader Db_CommandReader(string SQL) ...{ try ...{ cmd = new OleDbCommand(SQL, Conn); cmd.CommandType = CommandType.StoredProcedure; OleDbDataReader Rs = cmd.ExecuteReader(); return Rs; } catch (Exception ex) ...{ MessageBox.Show("错误:因" + ex.Message + ",无法执行:" + SQL); return null; } } //返回数据DataSet数据集 public DataSet Db_CreateDataSet(string SQL) ...{ try ...{ cmd = new OleDbCommand(SQL, Conn); OleDbDataAdapter Adpt = new OleDbDataAdapter(cmd); DataSet Ds = new DataSet(); Adpt.Fill(Ds, "NewTable"); return Ds; } catch (Exception ex) ...{ MessageBox.Show("错误:因" + ex.Message + ",无法执行:" + SQL); return null; } } //返回数据DataReader数据集，不需要返回数据的修改，删除可以使用本函数 public bool Db_ExecuteNonquery(string SQL) ...{ try ...{ Db_Conn(); cmd = new OleDbCommand(SQL, Conn); try ...{ cmd.ExecuteNonQuery(); return true; } catch (Exception ex) ...{ MessageBox.Show("错误:因" + ex.Message + ",无法执行:" + SQL); return false; } } finally ...{ this.close(); } } //返回数据DataReader数据集，不需要返回数据的修改，删除可以使用本函数 public bool Db_ExecuteNonquery(string SQL, bool Connect) ...{ try ...{ if (Connect) Db_Conn(); cmd = new OleDbCommand(SQL, Conn); try ...{ cmd.ExecuteNonQuery(); return true; } catch (Exception ex) ...{ MessageBox.Show("错误:因" + ex.Message + ",无法执行:" + SQL); return false; } } finally ...{ if (Connect) this.close(); } } //返回数据DataReader数据集，返回数据 public String Db_Executequery(string SQL) ...{ try ...{ Db_Conn(); cmd = new OleDbCommand(SQL, Conn); try ...{ return cmd.ExecuteScalar().ToString(); } catch (Exception ex) ...{ MessageBox.Show("错误:因" + ex.Message + ",无法执行:" + SQL); return ""; } } finally