第十四章 数据库查询事例 上机1.2.3

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;namespace ConsoleApplication1{    class Program    {         private const string strConn=@"Data Source=.;Initial Catalog=MySchool;Integrated Security=True";        //string connString = "Data Source=.;Initial Catalog=MySchool;Integrated Security=True";        static void Main(string[] args)        {            Program pro=new Program ();            string userName = "admin";            string pwd = "0";            string strMsg = "输入无效";           bool b= pro. CheckUserInfo(userName, pwd,ref strMsg);            if (b)            {                Console.WriteLine(strMsg);            }            else            {                Console.WriteLine(strMsg);            }            Console.ReadLine();        }             //SqlConnection connection = new SqlConnection(connString);              public  bool CheckUserInfo(string userName ,string pwd,ref string strMsg)        {            SqlConnection connection = new SqlConnection(strConn);            try            {                string strSql = "select count(*) from Admin where LoginId='" + userName + "'and LoginPwd='" + pwd + "'";                Console.WriteLine(strSql);                connection.Open();               // Console.WriteLine("打开数据库链接");                SqlCommand comm = new SqlCommand(strSql, connection);                int iRet = (int)comm.ExecuteScalar();                strMsg = "确实有这个信息";                if (iRet != 1)                {                    strMsg = "输入无效";                    return false;                }                else                 {                    return true;                }            }            catch (Exception )            {                //Console.WriteLine(ex.Message);                //Console.WriteLine("出现了异常!");                strMsg = "信息错误";                strMsg = "发生异常";                return false;            }            finally            {                connection.Close();                Console.WriteLine("关闭数据库链接");            }                }             }}