C# 第十四章 上机1-5

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 str = @"Data Source=.;Initial Catalog=MySchool;Integrated Security=True";        static void Main(string[] args)        {            Program p = new Program();            p.ss();            p.caidan();            p.GetudentAmount();            Console.ReadLine();        }        public void ss() {            Console.WriteLine("请输入登录名:");            string userName = Console.ReadLine();            Console.WriteLine("请输入密码:");            string pwd = Console.ReadLine();            string strMsg = "用来保存信息";            bool y = sss(userName, pwd, ref strMsg);            if (y)            {                Console.WriteLine(strMsg);            }            else            {                Console.WriteLine("错误");            }                }        public void caidan()        {            do            {                Console.WriteLine("=========请选择操作键============");                Console.WriteLine("1.统计学生人数");                Console.WriteLine("2.查看学生名单");                Console.WriteLine("3.按学号查询学生姓名");                Console.WriteLine("4.按姓名查询学生信息");                Console.WriteLine("5.修改学生出生日期");                Console.WriteLine("6.删除学生记录");                Console.WriteLine("7.新增年纪信息");                Console.WriteLine("8.退出");                Console.WriteLine("====================================");                int q = int.Parse(Console.ReadLine());                switch (q)                {                    case 0:                        break;                    case 1:                        GetudentAmount();                        break;                    case 2:                        break;                    case 3:                        break;                    case 4:                        break;                    case 5:                        break;                    case 6:                        break;                    case 7:                        break;                    case 8:                        break;                    default:                        caidan();                        break;                }            } while (true);        }        public bool sss(string userName, string pwd, ref string strMsg)        {            SqlConnection c = new SqlConnection(str);            try            {                c.Open();                string r = "SELECT COUNT(*) FROM [MySchool].[dbo].[Admin] where LoginId='" + userName + "'and LoginPwd='" + pwd + "'";                Console.WriteLine(r);                SqlCommand e = new SqlCommand(r, c);                int i = (int)e.ExecuteScalar();                if (i > 0)                {                    strMsg = "登陆成功,确实有这个信息";                    return true;                }            }            catch (Exception ex)            {                strMsg = "登录失败";                Console.WriteLine(ex.Message);                return false;            }            finally            {                Console.WriteLine("苏琳琳大美女");                c.Close();            }            return false;        }        public void  GetudentAmount() {            SqlConnection conn = new SqlConnection(str);            try            {                string strsql = "select count(*) from Student";                conn.Open();                SqlCommand comm = new SqlCommand(strsql,conn);                int iret = (int)comm.ExecuteScalar();                Console.WriteLine(iret);            }            catch (Exception ex)            {                Console.WriteLine(ex.Message);            }            finally {                conn.Close();            }                }    }}