写cookie
1 HttpCookie cookie = new HttpCookie("Info");//定义cookie对象以及名为Info的项
2 DateTime dt = DateTime.Now;//定义时间对象
3 TimeSpan ts=new TimeSpan(1,0,0,0);//cookie有效作用时间，具体查msdn
4 cookie.Expires = dt.Add(ts);//添加作用时间
5 cookie.Values.Add("user","cxbkkk");//增加属性
6 cookie.Values.Add("userid","1203");
7 Response.AppendCookie(cookie);//确定写入cookie中

读取cookie
1 if(Request.Cookies["Info"]!=null)
2 {
3     string temp=Convert.ToString(Request.Cookies["Info"].Values["user"])+" "+Convert.ToString(Request.Cookies["Info"].Values["userid"]);
4     //读全部就用Request.Cookies["Info"].Value)
5     if(temp=="")
6     {
7         Response.Write("空");
8     }
9     else
10         Response.Write(temp);
11 }
12 else
13 {
14     Response.Write("error");
15 }

修改cookie
1 Response.Cookies["Info"]["user"] = "2";
2 Response.Cookies["Info"].Expires = DateTime.Now.AddDays(1);

删除cookie下的属性
1 HttpCookie acookie=Request.Cookies["Info"];
2 acookie.Values.Remove("userid");
3 acookie.Expires = DateTime.Now.AddDays(1);
4 Response.Cookies.Add(acookie);

删除所有cookie，就是设置过期时间为现在就行了
1 int limit=Request.Cookies.Count - 1;
2 for(int i=0;i3 {
4     acookie = Request.Cookies(i)
5     acookie.Expires = DateTime.Now.AddDays(-1)
6     Response.Cookies.Add(acookie)
7 }

以下是在工作中遇到的问题：

在珠海知道啦，点击支持按扭时，数量加1。点过则不允许在点!

  #region btn_AddSupports_Click
  ///

   if (Request.Cookies[cookieName] == null)
   {
    
    HttpCookie cookie = new HttpCookie(cookieName);
    Response.Cookies.Add(cookie);
    
    if (this.questionId > 0)
    {
     bool result = DAL.ZhiDao.Question.AddSupports(this.questionId, this.SystemId);
     if (result)
     {
      this.item.Supports++;
     }
    }

    this.lbl_support.Text = this.item.Supports.ToString();
    this.lbl_Message.Text = "谢谢支持！";
   }
   else
   {
    this.lbl_Message.Text = "您已点击过！";
   }
  }
  #endregion