.net关于连接access的DBHelper

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;
using System.Data;
using System.Data.OleDb; //添加引用

using System.Web;

namespace xxxDAL
{
public class DBHelper
{
//引导<a href="http://lib.csdn.net/base/mysql" class='replace_word' title="MySQL知识库" target='_blank' style='color:#df3434; font-weight:bold;'>数据库</a>连接数据库调用Web.Config文件 
private static OleDbConnection connection;
private static String constr = System.Configuration.ConfigurationManager.AppSettings["provider"].ToString() + System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["dbPath"]) + ";";

//创建连接|DataDirectory|/SchoolDB.mdb
public static OleDbConnection Connection
{
get
{
OleDbConnection myConn = new OleDbConnection(constr);
string connectionString = myConn.ConnectionString;
if (connection == null)
{
connection = new OleDbConnection(connectionString);
//打开连接
connection.Open();
}
else if (connection.State == System.Data.ConnectionState.Closed)
{
connection.Open();
}
else if (connection.State == System.Data.ConnectionState.Broken)
{
connection.Close();
connection.Open();
}
return connection;
}
}
//（无参）返回执行的行数(删除修改更新)
public static int ExuteCommand(string safeSql)
{
OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
int result = cmd.ExecuteNonQuery();
return result;
}
//（有参）
public static int ExuteCommand(string sql, params OleDbParameter[] values)
{
OleDbCommand cmd = new OleDbCommand(sql, Connection);
cmd.Parameters.AddRange(values);
return cmd.ExecuteNonQuery();
}
//（无参）返回第一行第一列(删除修改更新)
public static int GetScalar(string safeSql)
{
OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
int result = Convert.ToInt32(cmd.ExecuteScalar());
return result;
}
//（有参）
public static int GetScalar(string sql, params OleDbParameter[] values)
{
OleDbCommand cmd = new OleDbCommand(sql, Connection);
cmd.Parameters.AddRange(values);
int result = Convert.ToInt32(cmd.ExecuteScalar());
return result;
}
//返回一个DataReader（查询）
public static OleDbDataReader GetReader(string safeSql)
{
OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
OleDbDataReader reader = cmd.ExecuteReader();
return reader;
}
public static OleDbDataReader GetReader(string sql, params OleDbParameter[] values)
{
OleDbCommand cmd = new OleDbCommand(sql, Connection);
cmd.Parameters.AddRange(values);
OleDbDataReader reader = cmd.ExecuteReader();
return reader;
}

//返回一个DataTable
public static DataTable GetTable(string safeSql)
{
DataSet ds = new DataSet();
OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
da.Fill(ds);
return ds.Tables[0];
}
public static DataTable GetTable(string sql, params OleDbParameter[] values)
{
DataSet ds = new DataSet();
OleDbCommand cmd = new OleDbCommand(sql, Connection);
cmd.Parameters.AddRange(values);
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
da.Fill(ds);
return ds.Tables[0];
}
}
}

 web.config中需要添加

<add key="provider" value="Provider=Microsoft.Jet.OLEDB.4.0;data source="/>
<add key="dbPath" value="~/App_Data/xxx(你的数据库).mdb"/>