asp.net cookies record the number of user logins and prevent duplicate logins to the same account

ASP tutorial. NET Cookies record the number of user logons and prevent the same account from repeatedly logging on

Place on the successful landing:

string key = TextBox1.Text///Username text box set to cache keyword
String uer = Convert.ToString (Cache[key]); Read the user's corresponding value in the cache
if (Uer = null | | uer = = String.Empty)//Judge whether the cache has a user's information, if there is no relevant value, indicating that the user did not log in
{
Define cache Expiration Time
TimeSpan sesstimeout = new TimeSpan (0, 0, system.web.httpcontext.current.session.timeout, 0, 0);
Insert a user-related cache value on the first landing
Httpcontext.current.cache.insert (key, key, NULL, DateTime.MaxValue, Sesstimeout, System.web.caching.cacheitempriority.notremovable, NULL);
session["Adminid"] = TextBox1.Text;
Response.Redirect ("main.aspx");
}
Else
{
Repeat Login Response.Write (' Your account has landed! ') ("<script>alert"); window.location= ' login.aspx ';</script> ");
}

Number plus 1

if (request.cookies["logincount"] = = null)
{
HttpCookie c= New HttpCookie ("Logincount");;
response.cookies["Logincount"].value = "1";
response.cookies["Logincount"].expires = datetime.now.adddays (1);
Response.Cookies.Add (c);
}
Else
{
int count = Convert.ToInt32 (request.cookies["Logincount"].value) + 1;
response.cookies["Logincount"].value = count.tostring ();
}

 if (request.cookies["Usercookie"] = = null)
{
HttpCookie usercookie = new HttpCookie ("Usercookie");
usercookie.values["username"] = userinfo.username.tostring ();
usercookie.values["lastvist"] = DateTime.Now.ToString ();
usercookie.values["Count" = "1";
Usercookie.expires = datetime.now.adddays (30);
Response.Cookies.Add (Usercookie);
}
Else
{
int counter = Convert.ToInt32 (request.cookies["Usercookie"] ["count"]) + 1;
HttpCookie UserC Ookie = new HttpCookie ("Usercookie");
usercookie.values["username"] = userinfo.username.tostring ();
usercookie.values["lastvist"] = DateTime.Now.ToString ();
usercookie.values["Count"] = counter.tostring ();
Usercookie.expires = datetime.now.adddays (30);
Response.Cookies.Add (Usercookie);
}

Fetch on another page
//Read Cookie
String namecookie = request.cookies["Usercookie" ["username"];
Response.Write (" User name: "+ Namecookie";
String Timecookie = request.cookies["Usercookie" ["lastvist"];
Response.Write ("<br> Upload access time:" + Timecookie);
String Countcookie = request.cookies["Usercookie" ["Count"];
Response.Write ("<br> Hits: + Countcookie");