private void OnForumSelected()
        {
            ChatRoomView      page      = new ChatRoomView();
            ChatRoomViewModel viewModel = new ChatRoomViewModel(page, this.SelectedForum.ChatDetail);

            page.BindingContext = viewModel;

            NavigationHandler.GlobalNavigator.Navigation.PushAsync(page);
            SelectedForum = null;
        }
        private async Task GetForumViewModel(List <ChatRoomDetail> forumList, List <Course> courseList)
        {
            ObservableCollection <ForumListItemViewModel> forumViewModelList = new ObservableCollection <ForumListItemViewModel> ();

            foreach (var course in courseList)
            {
                foreach (ChatRoomDetail item in forumList)
                {
                    if (course.CourseId == item.CourseID)
                    {
                        ForumListItemViewModel vm = new ForumListItemViewModel(item);
                        RawForumList.Add(vm);
                    }
                }
            }
            ForumList = new ObservableCollection <ForumListItemViewModel> (RawForumList);
        }