public TransactionObject SendFriendRequest(int senderUserID, int receiverUserID) { TransactionObject response = new TransactionObject(); if (!(frManager.CheckExistence(senderUserID, receiverUserID))) { try { User senderUser = userManager.GetUser(senderUserID); User receiverUser = userManager.GetUser(receiverUserID); FriendRequest fr = new FriendRequest(); fr.Requester = senderUser; fr.RequestTo = receiverUser; senderUser.SentFriendRequests.Add(fr); receiverUser.ReceivedFriendRequests.Add(fr); uow.Save(); } catch (Exception ex) { response.IsSuccess = false; response.Explanation = base.GetExceptionMessage(ex); } } else { response.IsSuccess = false; response.Explanation = "This friend request has been sent before and waiting to be responsed!"; } return response; }