植物的光合作用是什么:using System;

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.SqlClient;

public partial class Login1 : System.Web.UI.Page
{
public SqlCommand Cmd;
public SqlConnection Conn;
public DataSet Ds = new DataSet();
public string SqlStr; //定义SQL语句
public string ConStr;
//public string VersionNumber = ConfigurationManager.AppSettings["Version_Number"];

/* protected void Page_Load(object sender, EventArgs e)
{
//显示版本号
//lbl_VersionNumber.Text = VersionNumber;
ConStr = ConfigurationManager.AppSettings["Sql"] + Server.MapPath(".") + ConfigurationManager.AppSettings["Sql_name"];
}*/
//连接数据库
protected void GetData()
{
//ConStr = ConfigurationManager.AppSettings["Sql"] + Server.MapPath(".") + ConfigurationManager.AppSettings["Sql_admin"];
Conn = new SqlConnection(ConStr);
Conn.Open();
}

//登录按钮，核对用户名和密码……
protected void btn_submit_Click(object sender, EventArgs e)
{
GetData();

SqlStr = "SELECT TOP 1 * FROM admin WHERE U_Name = @u_name AND U_Password = @u_pwd";
Cmd = new SqlCommand(SqlStr, Conn);
//Cmd.Parameters.Add(new SqlParameter("@u_name", SqlType.Char, 10));
Cmd.Parameters["@u_name"].Value = Server.HtmlEncode(txt_name.Text);
//Cmd.Parameters.Add(new SqlParameter("@u_pwd", SqlType.Char, 10));
Cmd.Parameters["@u_pwd"].Value = Server.HtmlEncode(txt_pwd.Text);
SqlDataReader dr;
dr = Cmd.ExecuteReader();
if (dr.Read())
{
Session["login"] = "login"; //已经登录
Session["name"] = dr["U_Name"];
Session["pwd"] = dr["U_Password"];
Response.Redirect("index.html");
}
else
{
lbl_Message.Text = "<script language='javascript'> alert('用户名或密码错误!');location.href=location.href;</script>";
}

dr.Close();
Cmd.Dispose();
Conn.Close();
}
}