ADO.NET中与SQL Server连接类

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

/// <summary>
/// dbaccess 的摘要说明。
/// </summary>
public class dbaccess
{
public dbaccess()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
public static string _connString =System.Configuration.ConfigurationSettings.AppSettings["connString"];
public static SqlConnection _connection=new SqlConnection(_connString);
public static SqlDataReader dtr;

//打开连接
public static void Open()
{
if (_connection.State==ConnectionState.Closed)
{
_connection.Open();
}

}

//关闭连接

public static void Close()
{
if (_connection.State ==ConnectionState.Open)
{
_connection.Close();
}

}

//断开查询方式，返回数据集

public static DataSet RunSelect(string strSQL)

{
SqlCommand myCommand=new SqlCommand(strSQL,_connection);
DataSet ds =new DataSet();
SqlDataAdapter myAdapter=new SqlDataAdapter();
myAdapter.SelectCommand=myCommand;
try
{
Open();
myAdapter.Fill(ds);
}
catch
{}
finally
{
Close();
myAdapter.Dispose();
}
return ds;

}

//连接查询

public static SqlDataReader ExecuteReader(string strSql)
{
SqlCommand myCommand=new SqlCommand(strSql,_connection);
try
{
Open();
dtr=myCommand.ExecuteReader();
dtr.Read();
}
catch
{}
finally
{
myCommand.Dispose();
// dtr.Close();
// Close();
}
return dtr;
}

//执行SQL命令（插入，修改，删除）
public static void Execute(string strSql)
{
SqlCommand myCommand=new SqlCommand(strSql,_connection);
try
{
Open();
myCommand.ExecuteNonQuery();
}
catch
{}
finally
{
myCommand.Dispose();
Close();
}
}

}