using System;  using System.Collections.Generic;  using System.Linq;  using System.Text;  using System.Data.OleDb;  using System.Data;    namespace AccessOperator  {      class AccessHelper      {          private string conn_str = null;          private OleDbConnection ole_connection = null;          private OleDbCommand ole_command = null;          private OleDbDataReader ole_reader = null;          private DataTable dt = null;            /// <summary>          /// 构造函数          /// </summary>          public AccessHelper()          {              conn_str = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source='D:\我的文档\Visual Studio 2008\Projects\AccessOperator\AccessOperator\bin\Debug\myDb.mdb'";              InitDB();          }            private void InitDB()          {              ole_connection = new OleDbConnection(conn_str); //创建实例              ole_command = new OleDbCommand();          }            /// <summary>          /// 构造函数          /// </summary>          /// <param name="db_path">数据库路径</param>          public AccessHelper(string db_path)          {              conn_str = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" + db_path + "'";              InitDB();          }            /// <summary>          /// 转换数据格式          /// </summary>          /// <param name="reader">数据源</param>          /// <returns>数据列表</returns>          private DataTable ConvertOleDbReaderToDataTable(ref OleDbDataReader reader)          {              DataTable dt_tmp = null;              DataRow dr = null;              int data_column_count = 0;              int i = 0;                data_column_count = reader.FieldCount;              dt_tmp = BuildAndInitDataTable(data_column_count);                if (dt_tmp == null)              {                  return null;              }                while (reader.Read())              {                  dr = dt_tmp.NewRow();                    for (i = 0; i < data_column_count; ++i)                  {                      dr[i] = reader[i];                  }                    dt_tmp.Rows.Add(dr);              }                return dt_tmp;          }            /// <summary>          /// 创建并初始化数据列表          /// </summary>          /// <param name="Field_Count">列的个数</param>          /// <returns>数据列表</returns>          private DataTable BuildAndInitDataTable(int Field_Count)          {              DataTable dt_tmp = null;              DataColumn dc = null;              int i = 0;                if (Field_Count <= 0)              {                  return null;              }                dt_tmp = new DataTable();                for (i = 0; i < Field_Count; ++i)              {                  dc = new DataColumn(i.ToString());                  dt_tmp.Columns.Add(dc);              }                return dt_tmp;          }            /// <summary>          /// 从数据库里面获取数据          /// </summary>          /// <param name="strSql">查询语句</param>          /// <returns>数据列表</returns>          public DataTable GetDataTableFromDB(string strSql)          {              if (conn_str == null)              {                  return null;              }                try              {                  ole_connection.Open(); //打开连接                    if (ole_connection.State == ConnectionState.Closed)                  {                      return null;                  }                    ole_command.CommandText = strSql;                  ole_command.Connection = ole_connection;                    ole_reader = ole_command.ExecuteReader(CommandBehavior.Default);                    dt = ConvertOleDbReaderToDataTable(ref ole_reader);                    ole_reader.Close();                  ole_reader.Dispose();              }              catch (System.Exception e)              {                  Console.WriteLine(e.ToString());              }              finally              {                  if (ole_connection.State != ConnectionState.Closed)                  {                      ole_connection.Close();                  }              }                return dt;          }            /// <summary>          /// 执行sql语句          /// </summary>          /// <param name="strSql">sql语句</param>          /// <returns>返回结果</returns>          public int ExcuteSql(string strSql)          {              int nResult = 0;                try              {                  ole_connection.Open(); //打开数据库连接                  if (ole_connection.State == ConnectionState.Closed)                  {                      return nResult;                  }                    ole_command.Connection = ole_connection;                  ole_command.CommandText = strSql;                    nResult = ole_command.ExecuteNonQuery();              }              catch (System.Exception e)              {                  Console.WriteLine(e.ToString());                  return nResult;              }              finally              {                  if (ole_connection.State != ConnectionState.Closed)                  {                      ole_connection.Close();                  }              }                return nResult;          }            static void Main(string[] args)          {              AccessHelper Helper = new AccessHelper();              DataTable dt = Helper.GetDataTableFromDB("select * from test");                foreach (DataRow dr in dt.Rows)              {                  Console.WriteLine(dr[0].ToString()+" "+dr[1].ToString());              }                Console.WriteLine(Helper.ExcuteSql("insert into test(test) values ('hello')"));          }      }  }