C#

List<string> rangeDataMappingsToClear= new List<string>();
Dictionary<string, object> rangeDataMappings = new Dictionary<string, object>();
Dictionary<string, List<string>> rangeKeyMappings = new Dictionary<string, List<string>>();

foreach (string key in rangeDataMappingsToClear)
                {
                    rangeDataMappings.Remove(key);
               foreach (List<string> formulaKeys in rangeKeyMappings.Values)
                    {
                        while (formulaKeys.Remove(key)) { }
                    }
                }
                rangeDataMappingsToClear.Clear();

/// <summary>
       /// event fire when the user 1st browse the website
       /// </summary>
       protected void Application_PreRequestHandlerExecute(object sender, EventArgs e)
       {
           //Response.Write("Fire up");

           //if session items is not null
           if (HttpContext.Current.Session != null)
           {
               Response.Write("SessionID:" + Session.SessionID.ToString() + "User Key:" +(string)Session["users"]);

               //fires after initial login
               if (Session["users"] != null)
               {


                  String sKey= (string)Session["users"];
                  string sUser = (String)HttpContext.Current.Cache[sKey];
               }
               //remove the cache item if session is over
               else
               {

                   foreach (DictionaryEntry dEntry in HttpContext.Current.Cache)
                   {
                       HttpContext.Current.Cache.Remove(dEntry.Key.ToString());
                   }

               }
           }



       }

String sKey = Login1.UserName + Login1.Password;
                    string sUser = Convert.ToString(Cache[sKey]);

                    //no cache item
                    if (sUser == null || sUser==" ")
                    {


                        TimeSpan sesstimeout = new TimeSpan(0, 0, HttpContext.Current.Session.Timeout, 0, 0);
                        HttpContext.Current.Cache.Insert(sKey, sKey, null, DateTime.MaxValue, sesstimeout, System.Web.Caching.CacheItemPriority.NotRemovable, null);
                        Session["user"] = Login1.UserName + Login1.Password;
                    }
                    else
                    {
                        HttpContext.Current.Response.Write("User is already Login");
                    }