using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.OleDb;
public partial class login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//以下产生随机的验证码，并在label1显示
Random ro = new Random();
if (!IsPostBack)
{
this.Label1.Text = ro.Next(1000, 9999).ToString();
}
}
protected void Button1_Click(object sender, EventArgs e)
{

if (this.name.Text != "")//判断用户名是否未空
{
if (this.pwd.Text != "")//判断密码是否未空
{
if (this.yanzhen1.Text != "")//判断验证码是否未空
{
if (this.yanzhen1.Text == this.Label1.Text)//判断验证码是否相等
{
string sql;
sql = "select count(*) from userinfo where username='" + this.name.Text + "' and pwd='" + this.pwd.Text + "'";//建立sql查询语句
try
{
OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" + Server.MapPath("./app_data/db.mdb"));//建立数据库连接
conn.Open();
OleDbCommand cmd = new OleDbCommand(sql, conn);
int state =Convert.ToInt32( cmd.ExecuteScalar());//执行sql语句，并返回获得值
if (state == 0 || state > 1)//如果数据中没有记录或有多条记录则抱错
{
this.Label2.Text = "用户不存在，请检测用户名和密码是否正确！";
}
else
{
this.Label2.Text = "登入成功！" ;


}
conn.Close();

}
catch (Exception a)
{
Response.Writea.Message);
}
}
else
{
this.Label2.Text = "验证码不正确，请重新输入！";
}
}
else
{
this.Label2.Text = "验证码没有填写！";

}
}
else
{
this.Label2.Text = "密码没有填写！";

}
}
else
{
this.Label2.Text = "用户名没有填写！";
}
}
}