public DiscussionsViewModel() 
 {
     discussionDao = new DiscussionDao();
     userDao = new UserDao();
     postDao = new PostDao();
     postService = new PostService();
     discussions = discussionDao.getDiscussionsFromClass(ContextUtil.Instance.Class);
 }
 public PostsViewModel(IAsyncPlayer player)
 {
     contextualSelection = false;
     postDao = new PostDao();
     userDao = new UserDao();
     postService = new PostService();
     discussionDao = new DiscussionDao();
     posts = new ObservableCollection<Post>(postDao.getPostsFromDiscussion(ContextUtil.Instance.Discussion));
     selectedDiscussion = discussionDao.getDiscussion(ContextUtil.Instance.Discussion);
     ContextUtil.Instance.postsBefore = selectedDiscussion.previousPosts;
     ContextUtil.Instance.postsAfter = selectedDiscussion.nextPosts;
     manager = new TTSManager(player);
 }