注：取决于这个quetion
你好。 我有一个视图模型是这样的：
public class ViewModel {
private readonly IPersonService _personService;
private readonly ObservableCollection<SearchPersonModel> _foundedList;
private readonly DispatcherTimer _timer;
private readonly Dispatcher _dispatcher;
private CancellationTokenSource _tokenSource;
public SearchPatientViewModel(IPersonService personService) {
_personService = personService;
_foundedList = new ObservableCollection<SearchPersonModel>();
_dispatcher = (/*CurrentApplication*/).Dispatcher;
_timer = new DispatcherTimer(
TimeSpan.FromMilliseconds(1000),
DispatcherPriority.Normal,
TimerCallBack,
_dispatcher);
_tokenSource = new CancellationTokenSource();
}
public string Term {
get { return _term; }
set {
// implementing INotifyPropertyChanged
if(_term== value)
return;
_term= value;
OnPropertyChanged(() => Term);
tokenSource.Cancel(); // canceling prev search query
_timer.Stop(); // stop the timer to reset it
// start it again to do a search query if user change not the term for 1000ms
_timer.Start();
}
}
private void TimerCallBack(object sender, EventArgs e) {
_timer.Stop();
_tokenSource = new CancellationTokenSource();
var task = Task<IEnumerable<SearchPersonModel>>.Factory
.StartNew(Search, _tokenSource.Token);
_dispatcher.BeginInvoke((Action)(() => {
_foundedList.Clear();
foreach(var item in task.Result)
_foundedList.Add(item);
}), DispatcherPriority.Background);
}
private IEnumerable<SearchPersonModel> Search() {
return _personService.DoSearch(this.Term);
}
}
而在IPersonService实现我这样做：
public class PersonService : IPersonService {
public IEnumerable<SearchPersonModel> DoSearch(string term){
System.Threading.Thread.Sleep(10000);
return some-search-result;
}
}
但是，我希望，虽然搜索执行查询时，GUI是免费的。 但它冻结！ 你有任何想法，是我的错？ 你能帮我吗？ 提前致谢！
