c# - Write similar logic using generics -

i have following method determines cars need delete db.

private list<cardto> buildcarstodelete(ilist<cardto> newcars, ilist<cardto> existingcars) {     var missingcars = new list<cardto>();      var cars = newcars.select(c => c.carid);     var newcarids = new hashset<int>(cars);      foreach (var car in existingcars)     {         //if there no new cars had , have been removed         if (newcars.count() == 0)         {             missingcars.add(car);         }         else         {             if (!newcarids.contains(car.carid))             {                 missingcars.add(car);             }         }     }      return missingcars; } 

this works want - if want achieve same functionality customers or apartments of other dtos copying pasting code changing variable names , type of dto around - there nicer way possible using generics keep algorithm , logic allow me use on dto?

if ids of type int can passing in func determine id.

private list<t> buildtodelete<t>(     ilist<t> newitems,      ilist<t> existingitems,      func<t, int> getid) {     var missingitems = new list<t>();      var items = newitems.select(getid);     var newitemids = new hashset<int>(items);      foreach (var item in existingitems)     {         if (newitems.count() == 0)         {             missingitems.add(item);         }         else         {             if (!newitemids.contains(getid(item)))                  {                 missingitems.add(item);             }         }     }      return missingitems; } 

then call shown below:

var results = buildtodelete(newcars, existingcars, c => c.carid);