public void AddTab(TabItemViewModel vm) { if (vm is VideoViewModel) { VideoTabs.Add(vm); } else if (vm is UserViewModel) { UserTabs.Add(vm); } else if (vm is PublicMylistViewModel) { MylistTabs.Add(vm); } else if (vm is CommunityViewModel) { CommunityTabs.Add(vm); } else if (vm is LiveViewModel) { LiveTabs.Add(vm); } else if (vm is PlayListViewModel) { PlayListTabs.Add(vm); } else { TabItems.Add(vm); } }