asp.net初学者必读<2>

常用代码：

1、检查Cookies是否打开：

if (Request.Cookies["CheckCode"] == null)
        {
            Response.Write("<script language=javascript>alert('您的浏览器设置已被禁用 Cookies，您必须设置浏览器允许使用 Cookies 选项后才能使用本系统。')</script>");
            return;
        }

 

2、对字符串作比较：

String.Compare(Request.Cookies["CheckCode"].Value, txtCheckCode.Text.ToUpper(), true) != 0

 

3、连接字符串

请在使用这段之前添加引用：using System.Data.SqlClient;  ///引入命名空间。

SqlConnection Con = new SqlConnection(ConfigurationManager.AppSettings["ConSQL"]);
                Con.Open();
                SqlCommand Com = new SqlCommand("select * from tb_User where UserName='" + this.txtName.Text + "' and PassWord='" + this.txtPwd.Text + "' and Popedom='0'", Con);
                SqlDataReader dr = Com.ExecuteReader();
                dr.Read();

 

插入一条记录：

string cmdtxt = "INSERT INTO tb_LoginLog(UserName,LoginTime,LoginIP)";
                    cmdtxt += " VALUES('" + dr["UserName"].ToString() + "','" + DateTime.Now + "','" + Request.UserHostAddress + "')";
                    SqlData da = new SqlData();
                    da.ExceSQL(cmdtxt);

4、判断是否有记录

dr.HasRows

 

5、获取记录集中的某个字段

dr["UserName"]，可以调用一个公共方法ToString()进行类型转换。

 

6、session的使用

Session["Name"] = ""注意这里是[ ]中括号。

 

附：一个完整的登录代码

 

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;  ///引入命名空间

public partial class IndexFrame_Main : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnOK_Click(object sender, EventArgs e)
    {
        if (Request.Cookies["CheckCode"] == null)
        {
            Response.Write("<script language=javascript>alert('您的浏览器设置已被禁用 Cookies，您必须设置浏览器允许使用 Cookies 选项后才能使用本系统。')</script>");
            return;
        }

        if (this.CheckBox1.Checked)
        {
            if (String.Compare(Request.Cookies["CheckCode"].Value, txtCheckCode.Text.ToUpper(), true) != 0)
            {
                Response.Write("<script language=javascript>alert('验证码错误，请重新输入！')</script>");
                return;
            }
            else
            {
                SqlConnection Con = new SqlConnection(ConfigurationManager.AppSettings["ConSQL"]);
                Con.Open();
                SqlCommand Com = new SqlCommand("select * from tb_User where UserName='" + this.txtName.Text + "' and PassWord='" + this.txtPwd.Text + "' and Popedom='0'", Con);
                SqlDataReader dr = Com.ExecuteReader();
                dr.Read();
                if (dr.HasRows)
                {
                    Session["UserName"] = dr["UserName"].ToString();
                    Session["Name"] = dr["Name"].ToString();
                    Session["PassWord"] = dr["PassWord"].ToString();
                    Session["Popedom"] = dr["Popedom"].ToString();
                    Session.Timeout = 100;
                    string cmdtxt = "INSERT INTO tb_LoginLog(UserName,LoginTime,LoginIP)";
                    cmdtxt += " VALUES('" + dr["UserName"].ToString() + "','" + DateTime.Now + "','" + Request.UserHostAddress + "')";
                    SqlData da = new SqlData();
                    da.ExceSQL(cmdtxt);
                    Response.Redirect("Module/Index.aspx");
                }
                else
                {
                    Response.Write("<script language=javascript>alert('用户名或密码不正确！');</script>");
                }
                dr.Close();
            }
        }
        else
        {
            if (String.Compare(Request.Cookies["CheckCode"].Value, txtCheckCode.Text.ToUpper(), true) != 0)
            {
                Response.Write("<script language=javascript>alert('验证码错误，请重新输入！')</script>");
                return;
            }
            else
            {
                SqlConnection Con = new SqlConnection(ConfigurationManager.AppSettings["ConSQL"]);
                Con.Open();
                SqlCommand Com = new SqlCommand("select * from tb_User where UserName='" + this.txtName.Text + "' and PassWord='" + this.txtPwd.Text + "' and Popedom='1'", Con);
                SqlDataReader dr = Com.ExecuteReader();
                dr.Read();
                if (dr.HasRows)
                {
                    Session["UserName"] = dr["UserName"].ToString();
                    Session["Name"] = dr["Name"].ToString();
                    Session["PassWord"] = dr["PassWord"].ToString();
                    Session["Popedom"] = dr["Popedom"].ToString();
                    string cmdtxt = "INSERT INTO tb_LoginLog(UserName,LoginTime,LoginIP)";
                    cmdtxt += " VALUES('" + dr["UserName"].ToString() + "','" + DateTime.Now + "','" + Request.UserHostAddress + "')";
                    SqlData da = new SqlData();
                    da.ExceSQL(cmdtxt);
                    Response.Redirect("Module/Index.aspx");
                }
                else
                {
                    Response.Write("<script language=javascript>alert('用户名或密码不正确！');</script>");
                }
                dr.Close();
            }
        }
    }
}