c# - 长后台进程刷新 ui wpf

Question

我有很长的搜索操作，会定期更新 UI(发现事件 -> 更新 UI)

我尝试了很多方法来实现它:

1. 异步/等待

   public void PushButton()
   {
       await AsyncSearchAll();
   }
   
   public async Task AsyncSearchAll(SearchPanelViewModel searchPanelViewModel, SearchSettings searchSettings, CancellationToken cancellationToken)
   {
       await Task.Factory.StartNew(() =>
                                         {
                                             //searching for occurence
                                             //write it into panel
                                         }, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.FromCurrentSynchronizationContext());
   }
   

2. 后台 worker

   我想使用它，但我不想只使用 .ReportProgress() 访问 UI

3. 调用 Dispatcher.BeginInvoke(()=>{//updating UI}) 的简单后台线程

   /// <summary>
   ///     Interaction logic for MainWindow.xaml
   /// </summary>
   public partial class MainWindow
   {
       public MainWindow()
       {
           InitializeComponent();
       }
   
       private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
       {
           var backgroundThread = new Thread(CountToTen)
               {
                   IsBackground = true
               };
           backgroundThread.Start();
       }
   
       private void CountToTen()
       {
           for (int i = 1; i <= 10000; i++)
           {
               var j = i;
               Dispatcher.BeginInvoke(new Action(() => Seconds.Text = j.ToString(CultureInfo.InvariantCulture)));
           }
       }
   

所有方法在完成线程后写入所有数据。 有什么方法可以运行后台任务来定期更新 UI 而不会通过阻止 ui 减慢程序速度？

Answer 1

最好将“工作人员”逻辑与“UI 更新”逻辑分开。

像这样:

public async Task AsyncSearchAll(SearchPanelViewModel searchPanelViewModel, SearchSettings searchSettings, CancellationToken cancellationToken)
{
  while (..)
  {
    var results = await Task.Run(() => /* search more */);
    /* update panel with results */
  }
}

但是如果你想要实际的进度更新，也有办法做到这一点:

public async void PushButton()
{
  Progress<MyUpdateType> progress = new Progress<MyUpdateType>(update =>
  {
    /* update panel */
  });
  await Task.Run(() => SearchAll(..., progress));
}

public void SearchAll(SearchPanelViewModel searchPanelViewModel,
    SearchSettings searchSettings, CancellationToken cancellationToken,
    IProgress<MyUpdateType> progress)
{
  while (..)
  {
    /* search more */
    if (progress != null)
      progress.Report(new MyUpdateType(...));
  }
}