尝试

Try

if(Request.Cookies["userinfo"]!=null)
{
   var value=Request.Cookies["userinfo"].Value;
}

if（Request.Cookies [userinfo]！= null）

{

Session [uname] = Request.Cookies [userinfo]。值[username];

Session [userid] = Request.Cookies [userinfo] .Values [userid];

}

if (Request.Cookies["userinfo"] != null)
{
Session["uname"] = Request.Cookies["userinfo"].Values["username"];
Session["userid"] = Request.Cookies["userinfo"].Values["userid"];
}