c# - Clear list but retain Session -

i have code list shown,

var refinedclaimsearchnew = new claimsearch(); (int = 1; < refinedictionary.length; i++) {     list<claimsearchdatavalues> claimtable = new list<claimsearchdatavalues>();     int count = i;      if (count == 1) { claimtable = refinedclaimsearch.rowvalues; }     else { //my problem in else loop            claimtable = (list<claimsearchdatavalues>)session["test"];//get list out of session            if (refinedclaimsearchnew.rowvalues != null) { refinedclaimsearchnew.rowvalues.clear(); //and clear list retain session value}           }      var dictionaryitems = refinedictionary[i];     string[] dictionaryitemssplit = dictionaryitems.split(',');      (int j = 1; j < dictionaryitemssplit.length; j++)     {        var nodeelement = dictionaryitemssplit[j];        foreach (var row in claimtable)        {           var currentrow = row;           bool hasrefinevalue = false;           foreach (var rowvalues in currentrow.cellvalues)           {               if (rowvalues.key == nodeelement || rowvalues.value == nodeelement)               {                   hasrefinevalue = true;               }           }           if (hasrefinevalue == true)           {              refinedclaimsearchnew.rowvalues.add(currentrow);           }        }     }     session["test"] = refinedclaimsearchnew.rowvalues;//storing list in session } 

i'm storing list in session , next iteration want remove stored list session @ same time clear list can use new list again.. looks when take list out of session-its fine, next line when clear() list, list retrieved session becomes 0.. please me know how that....