Session in C# using ASP.NET

we use on Login Page in VB
  Session.Add("userId", txtUserId.Text)
            Session.Add("userGroupID", userGroupIDList.Text)
            Session.Add("loginStatus", "true")
            Response.Redirect("main.aspx")
 
and Admin Page
loginStatus = Session.Item("loginStatus").ToString()
            userID = Session.Item("userID").ToString()
            userGroupID = Session.Item("userGroupID").ToString()

            If userID.ToLower <> "administrator" Then
                Response.Redirect("admin ...