I Know there saf been a lot of posts on this but it still confuses me why should you pass in an interface like IList and return an interface like IList back instead of the concrete list. From this it follows that your method implementation hayat represent its local variables https://c-object-kullan-m31738.eqnextwiki.com/4262669/c_ilist_nerelerde_kullanılıyor_için_5_İkinci_trick