private void Register()
        {
            string error = RegisterPageMemberModel.EnableValidationAndGetError();

            if (error != null)
            {
                return;
            }

            MemberModel tempMemberModel = new MemberModel();

            tempMemberModel.CopyFrom(RegisterPageMemberModel);

            MemberModels.members.Add(tempMemberModel);

            TreeCategory parent = TreeViewMaker.FindNewParent(TreeItemModel.TreeCategories, RegisterPageMemberModel.Age);

            if (parent != null)
            {
                parent.Children.Add(tempMemberModel);
            }

            RegisterPageMemberModel.Clear();
            MessageBoxService.MessageBoxServiceShow(registerCompletedMessage);
        }