第十四章 使用ADD.NET访问数据库

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 ent = @"Data Source=.;Initial Catalog=MySchool;Integrated Security=True; User ID=ru;Password=12";

static void Main(string[] args)
{
Program Q = new Program();
Q.su();

string names = "Admin";
string pass = "0";
string strMsg = "信息";
bool b = Q.CheckUserInfo( names, pass,ref strMsg);
if (b)
{
Console.WriteLine(strMsg);

}
else
{
Console.WriteLine(strMsg);
}
Console.ReadLine();

}

public void su()
{
Console.WriteLine("请输入用户名:");
string name = Console.ReadLine();
Console.WriteLine("请输入密码:");
int pass =int.Parse(Console.ReadLine());
if (pass != 000)
{
Console.WriteLine("登录失败");
}
else
{
Console.WriteLine("登录成功");
cg();
}

}

public void cg()
{
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.新增年纪记录");
Console.WriteLine("8.退出");
Console.WriteLine("================================");
int m=int.Parse(Console.ReadLine());
switch(m){
case 1:
Console.WriteLine("在校学生人数:"+qun());
break;
case 2:

break;
case 3:

break;
case 4:

break;
case 5:

break;
case 6:

break;
case 7:

break;
case 8:
Console.WriteLine("退出!");
break;
default:
Console.WriteLine("输入错误,请重新输入:");
break;

}

}

public int qun()
{
SqlConnection tuy = new SqlConnection(ent);
try
{
tuy.Open();
string re = "select count(StudentNo) from dbo.Student  ";
SqlCommand  du=new SqlCommand(re,tuy);
int we=(int)du.ExecuteScalar();
return we;
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
return -1;
}
finally
{
tuy.Close();
Console.WriteLine("关闭语句");

}

}

public bool CheckUserInfo(string names,string pass,ref string strMsg )
{

SqlConnection connection = new SqlConnection(ent);
try
{

connection.Open();
string rr = "select COUNT(*)as 总数 from [MySchool].[dbo].[Admin] where LoginId='" + names + "'and LoginPwd='" + pass + "'";

Console.WriteLine("打开数据库连接");
SqlCommand comm = new SqlCommand(rr, connection);
int ww = (int)comm.ExecuteScalar();
Console.WriteLine("打开"+ww+"连接");
if (ww != 1)
{
strMsg = "输入无效";
return false;
}
else
{
return true;
}
}
catch (Exception ex)
{

Console.WriteLine("出现异常:" + ex.Message);
Console.WriteLine("出现了问题");
strMsg = "发生异常";
return false;
}
finally
{
connection.Close();
Console.WriteLine("关闭数据库连接成功");

}

}

}
}