c#asp.net添加/修改/删除Cookie值

//添加Cookie

protected void Button2_Click(object sender, EventArgs e)
     {

            HttpCookie cookie1 = new HttpCookie("MyCookie");   //初使化并设置Cookie的名称
            //string Encryp1 = page.EncryptCookie(userName);    //用户名加密
            //string Encryp2 = page.EncryptCookie(userPwd);       //密码加密
            cookie1.Values.Add("loginName", Encryp1);//添加用户名
            cookie1.Values.Add("loginPwd", Encryp2);//添加密码
            Response.Cookies.Add(cookie1); //添加新建的cookie

}

//修改Cookie
    protected void Button3_Click(object sender, EventArgs e)
     {
        //获取客户端的Cookie对象
         HttpCookie cok = Request.Cookies["MyCook"];
        if (cok != null)
         {
         //修改Cookie的两种方法
             cok.Values["userid"] = "alter-value";
             cok.Values.Set("userid", "alter-value");
          //往Cookie里加入新的内容
              cok.Values.Set("newid", "newValue");
              Response.AppendCookie(cok);
         }
     }

//************************************************

//以下未进行验证
 //删除Cookie
    protected void Button4_Click(object sender, EventArgs e)
     {
         HttpCookie cok = Request.Cookies["MyCook"];
        if (cok != null)
         {
            if (!CheckBox1.Checked)
             {
                 cok.Values.Remove("userid");//移除键值为userid的值
             }
            else
             {
                 TimeSpan ts = new TimeSpan(-1, 0, 0, 0);
                 cok.Expires = DateTime.Now.Add(ts);//删除整个Cookie，只要把过期时间设置为现在
             }
             Response.AppendCookie(cok);
         }
     }