DBHelper.CS

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Data.Common;
using System.Collections.Generic;

//引用后，直接修改与项目相同的命名空间就可直接使用：DXApplication5
namespace DXApplication5
{

    class DBHelper
    {
        
        //数据库链接字符串
        public static string ConnString = "Data Source = 127.0.0.1;Initial Catalog = PulseSterilizer;User Id = sa;Password =sa;";

        //建立数据库链接
        public static SqlConnection conn = null;
        private static void InitConnection()
        {
            if (conn == null)
                conn = new SqlConnection(ConnString);
            if (conn.State == ConnectionState.Broken)
            {
                conn.Close();
                conn.Open();
            }
            if (conn.State == ConnectionState.Closed)
            {
                conn.Open();
            }

        }

        //获取DataReader
        public static SqlDataReader GetDataReader(string str)
        {
            InitConnection();
            SqlCommand cmd = new SqlCommand(str, conn);
            return cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }

        //查询，获取DataSet
        public static DataSet GetDataSet(string sqlStr)
        {
            InitConnection();
            DataSet ds = new DataSet();
            SqlDataAdapter dap = new SqlDataAdapter(sqlStr, conn);
            dap.Fill(ds);
            conn.Close();
            return ds;
        }

        //查询，获取DataTable
        public static DataTable GetDataTable(string sqlStr)
        {
            return GetDataSet(sqlStr).Tables[0];
        }

        //增删改
        public static int ExecuteNonQuery(string str)
        {
            InitConnection();
            SqlCommand cmd = new SqlCommand(str, conn);
            int result = cmd.ExecuteNonQuery();
            conn.Close();
            return result;
        }

        //执行集合函数
        public static object ExecuteScalar(string str)
        {
            InitConnection();
            SqlCommand cmd = new SqlCommand(str, conn);
            object result = cmd.ExecuteScalar();
            conn.Close();
            return result;
        }
    }

}