private async void OnClickedChatRoomLoginModal(object sender, EventArgs e)
        {
            ChatRoom chatRoom = new ChatRoom(12, "Hello Chat Room", "Chat Room Description", 1, "123");

            var page = new ModalPrivateChatRoomLoginPage(chatRoom, Navigation);
            await Navigation.PushPopupAsync(page);
        }
        void OnItemSelected(object sender, SelectedItemChangedEventArgs e)
        {
            ChatRoom chatRoom = e.SelectedItem as ChatRoom;

            if ((int)Enumerations.ChatRoomType.Public == chatRoom.Type)
            {
                var chatRoomItemPage = new ChatRoomItemPage(chatRoom);
                Navigation.PopAsync(true);
                Navigation.PushAsync(chatRoomItemPage);
            }
            else
            {
                var page = new ModalPrivateChatRoomLoginPage(chatRoom, Navigation);
                Navigation.PushPopupAsync(page);
            }
        }