ASP.NET中 Session、Application、Cookie的使用

一、Session的使用

//写入
String name = username.Text;
Session["username"] = name;
//判断
if(Session["username"] != null)
{
   //TODO
}

例:通过session传值，输入账号密码，点击登录，

在另外页面显示

点击返回可以查看在原先页面查看到登录的用户名

相关代码:

namespace class3
{
    public partial class test1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if(Session["username"] != null)
            {
                Label1.Text = "当前登录的用户是：" + Session["username"].ToString();
            }
        }

        //登录按钮
        protected void Button1_Click(object sender, EventArgs e)
        {
            String name = username.Text;
            Session["username"] = name;
            Response.Redirect("test1show.aspx");
        }
    }
}
namespace class3
{
    public partial class test1show : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            String name = "";
            if (Session["username"] != null)
            {
                name = Session["username"].ToString();
            }
            Label1.Text = "当前登录的用户是：" + name;

        }

        //页面返回按钮
        protected void Button1_Click(object sender, EventArgs e)
        {
            Response.Redirect("test1.aspx");
        }
    }
}

二、Application的使用

和Session的用法类似

//写入
Application["reng"] = 0;

例:获取登录的人数，点击退出后人数减少，记录总访问量

相关代码:

namespace class3
{
    public partial class test2show : System.Web.UI.Page
    {
        //初始化用户名
        private String name;
        //初始化密码
        private String pass;

        protected void Page_Load(object sender, EventArgs e)
        {
            //初始化在线人数
            int zaixian = (Application["zaixian"] == null) ? 0 : (int)Application["zaixian"];
            //初始化总人数
            int reng = (Application["reng"] == null) ? 0 : (int)Application["reng"];
            //判断是否是第一次提交
            Boolean isFirst = (reng == 0) ? true : false;
            //请求类型
            String method = "";

            method = Request.HttpMethod.ToUpper();

            //提交name和pass
            if (method == "POST")
            {
                name = Request.Form["username"];
                pass = Request.Form["password"];
            }

            //判断在线人数和总人数
            if(name !=null && pass != null)
            {
                if (isFirst)
                {
                    //初始在线人数为0
                    Application["zaixian"] = 0;
                    //初始总人数为0
                    Application["reng"] = 0;

                    //登录后
                    Application["zaixian"] = (int)Application["zaixian"] + 1;
                    Application["reng"] = (int)Application["reng"] + 1;

                    zaixian = (int)Application["zaixian"];
                    reng = (int)Application["reng"];
                }
                else
                {
                    //登录后
                    Application["zaixian"] = (int)Application["zaixian"] + 1;
                    Application["reng"] = (int)Application["reng"] + 1;
                    zaixian = (int)Application["zaixian"];
                    reng = (int)Application["reng"];
                }
            }
            
            Label1.Text = "在线人数：" + zaixian + "  总访问量：" + reng;
        }

        //退出按钮逻辑
        protected void Button1_Click(object sender, EventArgs e)
        {
            Application["zaixian"] = (int)Application["zaixian"] - 1;
            Response.Redirect("test2.aspx");
        }
    }
}

三、Cookie的使用

//写入
Response.Cookies["username"].Value = name;
//设置过期时间 7天
Response.Cookies["username"].Expires = DateTime.Now.AddDays(7);

例:将登录后的用户名进行记录，存入Cookie并设置过期时间

相关代码:

namespace class3
{
    public partial class test3show : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            //初始化用户名
            String name = "";
            //初始口令
            String pass = "";
            //请求类型
            String method = "";
            //是否选择存Cookie
            Boolean isSave = false;

            method = Request.HttpMethod.ToUpper();

            //提交name和pass
            if (method == "POST")
            {
                name = Request.Form["username"];
                pass = Request.Form["password"];
                isSave = (Request.Form["CheckBox1"] == null) ? false : true;
            }
            
            //判断是否存入
            if (isSave)
            {
                Response.Cookies["username"].Value = name;
                Response.Cookies["username"].Expires = DateTime.Now.AddDays(7);
                Response.Cookies["password"].Value = pass;
                Response.Cookies["password"].Expires = DateTime.Now.AddDays(7);
            }


            //输出
            Label1.Text = "用户名:" + name + "<br />" +
                            "口令:" + pass;
        }

        //返回按钮
        protected void Button1_Click(object sender, EventArgs e)
        {
            Response.Redirect("test3.aspx");
        }
    }
}

源码下载地址:https://download.youkuaiyun.com/download/dhywjx/10468324