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


 读取cookie 
 if(Request.Cookies["Info"]!=null) 
 { 
 　　string temp=Convert.ToString(Request.Cookies["Info"].Values["user"])+" "+Convert.ToString(Request.Cookies["Info"].Values["userid"]); 
 　　//读全部就用Request.Cookies["Info"].Value
 }
 if(temp=="") 
 { 
 　　Response.Write("空"); 
 } 
 else
 　　Response.Write(temp); 
 } 
 else
 { 
　　Response.Write("error"); 
 }



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



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



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