c#连接access数据库操作类分享

<configuration>
<appsettings/>
<connectionstrings>
<add name="connectionstring" connectionstring="provider=microsoft.jet.oledb.4.0;data source=d:\keleyi\app_data\db.mdb;jet oledb:database password=keleyi.com"
providername="system.data.oledb" />
</connectionstrings>

using system;
using system.data;
using system.data.oledb;
using system.web;
using system.web.ui;
using system.configuration;

namespace com.lxj.database
{
/// <summary>
/// conn 的摘要说明。
/// </summary>
public class conndbforacccess
{
/// <summary>
/// 连接数据库字符串
/// </summary>
private string connectionstring;

/// <summary>
/// 存储数据库连接（保护类，只有由它派生的类才能访问）
/// </summary>
protected oledbconnection connection;

/// <summary>
/// 构造函数：数据库的默认连接
/// </summary>
public conndbforacccess()
{
string connstr;
connstr = configurationmanager.connectionstrings["connectionstring"].connectionstring.tostring();
// connstr = system.configuration.configurationsettings.appsettings["connectionstring"].tostring(); //从web.config配置中读取
connectionstring = connstr;
//connectionstring = "provider=microsoft.jet.oledb.4.0;data source=" + httpcontext.current.request.physicalapplicationpath + connstr;
// connectionstring = system.configuration.configurationsettings.appsettings["connectionstring"].tostring();
//
connection = new oledbconnection(connectionstring);
}

/// <summary>
/// 构造函数：带有参数的数据库连接
/// </summary>
/// <param name="newconnectionstring"></param>
public conndbforacccess(string newconnectionstring)
{
//connectionstring = "provider=microsoft.jet.oledb.4.0;data source=" + httpcontext.current.request.physicalapplicationpath + newconnectionstring;
connectionstring = newconnectionstring;
connection = new oledbconnection(connectionstring);
}

/// <summary>
/// 获得连接字符串
/// </summary>
public string connectionstring
{
get
{
return connectionstring;
}
}

/// <summary>
/// 执行sql语句没有返回结果，如：执行删除、更新、插入等操作
/// </summary>
/// <param name="strsql"></param>
/// <returns>操作成功标志</returns>
public bool exesql(string strsql)
{
bool resultstate = false;

connection.open();
oledbtransaction mytrans = connection.begintransaction();
oledbcommand command = new oledbcommand(strsql, connection, mytrans);

try
{
command.executenonquery();
mytrans.commit();
resultstate = true;
}
catch
{
mytrans.rollback();
resultstate = false;
}
finally
{
connection.close();
}
return resultstate;
}

/// <summary>
/// 执行sql语句返回结果到datareader中
/// </summary>
/// <param name="strsql"></param>
/// <returns>datareader</returns>
private oledbdatareader returndatareader(string strsql)
{
connection.open();
oledbcommand command = new oledbcommand(strsql, connection);
oledbdatareader datareader = command.executereader();
connection.close();

return datareader;
}

/// <summary>
/// 执行sql语句返回结果到dataset中
/// </summary>
/// <param name="strsql"></param>
/// <returns>dataset</returns>
public dataset returndataset(string strsql)
{
connection.open();
dataset dataset = new dataset();
oledbdataadapter oledbda = new oledbdataadapter(strsql, connection);
oledbda.fill(dataset, "objdataset");

connection.close();
return dataset;
}

/// <summary>
/// 执行一查询语句，同时返回查询结果数目
/// </summary>
/// <param name="strsql"></param>
/// <returns>sqlresultcount</returns>
public int returnsqlresultcount(string strsql)
{
int sqlresultcount = 0;

try
{
connection.open();
oledbcommand command = new oledbcommand(strsql, connection);
oledbdatareader datareader = command.executereader();

while (datareader.read())
{
sqlresultcount++;
}
datareader.close();
}
catch
{
sqlresultcount = 0;
}
finally
{
connection.close();
}
return sqlresultcount;
}

}
}