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();

   }

  }

 }