记录登录状态

写入Cookie

Response.Cookies["UserName"].Value = "用户名"; 
Response.Cookies["CustomerID"].Expires = DateTime.Today.AddDays(30); 

读取Cookie

if (Request.Cookies["UserName"].Value != null) 
{ 
    //用户曾登录 
    string username = Request.Cookies["UserName"].Value;    
} 
else 
{ 
    //新用户须进入登录界面 
}