后台工作人员不更新 UI 并进入无限循环

Question

我收到了来自固件的回电。当我收到那个回电时，我想用适当的状态更新我的 UI。所以我属性更改了每次回调引发的事件，我正在后台线程中订阅该事件。

请在DoWork中查看类似的while(!WorkDone)。我正在阻止调用，因为我希望后台线程保留在 DoWork 中直到更新完成（我可以使用 ManualResetEvent 吗？）。问题是，即使我在 PropertyChanged 中将 WorkDone 设置为 true，它也永远不会被设置，并且我用来更新 UI 的 CurrentStatus 永远不会更新，并且程序会进入无限循环。请帮忙。

private void StartCurrentRun(bool obj)
{
    this.worker = new BackgroundWorker();
    this.worker.WorkerReportsProgress = true;
    this.worker.WorkerSupportsCancellation = true;
    StartTimer();
    PropertyCallBackChangedInstance.PropertyChanged -= PropertyCallBackChangedInstance_PropertyChanged;
    WhenCancelledBlurVolumesGrid = false;
    OriginalTime = SelectedVolumeEstimatedTime();
    this.worker.DoWork += this.DoWork;
    this.worker.ProgressChanged += this.ProgressChanged;
    this.worker.RunWorkerCompleted += Worker_RunWorkerCompleted;
    IsLiveProgress = true;
    this.worker.RunWorkerAsync();
}

private void DoWork(object sender, DoWorkEventArgs e)
{
    try
    {
        CreateEventLogs.WriteToEventLog(string.Format("Run with Assay:{0} Volume{1} has been started", SelectedAssay, SelectedVolume), LogInformationType.Info);
        var instance = ConnectToInstrument.InstrumentConnectionInstance;
        instance.InitalizeRun(PopulateRespectiveVolumes());
        PropertyCallBackChangedInstance.PropertyChanged += PropertyCallBackChangedInstance_PropertyChanged;
        while (!WorkDone)
        {
            continue;
        }
    }
    catch (Exception ex)
    {
        CreateEventLogs.WriteToEventLog(string.Format("{0} - {1}", "Error occured during Run", ex.Message), LogInformationType.Error);
    }
}

private void PropertyCallBackChangedInstance_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
    //bool stepDone = false;
    if (e.PropertyName == "RunStepStatusName")
    {
        var value = sender as InstrumentCallBackProperties;
        Dispatcher.CurrentDispatcher.BeginInvoke((Action)(() => {
            CurrentStatus = value.RunStepStatusName;

            if (value.RunStepStatusName == "Step5")
            {
                WorkDone = true;
            }
        }));
        //stepDone = true;
    }
}

private void ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    this.ProgressValue = e.ProgressPercentage;
}

这是 InitailizeRun 方法，当我调用它时我收到回调

public async void InitalizeRun(VolumeInfo volumeInfo)
{
    AssayInfo AssayInfo = new AssayInfo();
    AssayInfo.IVolume = volumeInfo;
    CartridgeStepStatus StepStatus = new CartridgeStepStatus();
    StepStatus.Data = AssayInfo;
    await Task.Run(() => _instrument.ProcessCartridge(StepStatus));
}

这里是我收到的回电我正在更新属性

public void ProcessCartidge<T>(T data)
{
    InstrumentCallBackPropertiesInstance.RunStepStatusName = data.ToString();
}

Answer 1

您可以将 BackgroundWorker 替换为 Task.Run，因为它不适用于 async 和 await。

Task.Run 启动一个后台线程，并且应该包含需要在单独线程上运行的代码。如果你想报告进度，你应该使用 IProgress 参数。

这个例子应该能让你朝着正确的方向前进。您可以在此基础上构建您的最终解决方案。

protected override async void OnLoadAsync( EventArgs e )
{
    base.OnLoad( e );

    try
    {
        IsLiveProgress = true;
        await StartCurrentRunAsync( true );
    }
    catch ( Exception ex )
    {
        CreateEventLogs.WriteToEventLog( string.Format( "{0} - {1}" , "Error occured during Run" , ex.Message ) , LogInformationType.Error );
    }
    finally
    {
        IsLiveProgress = false;
    }
}

private Task StartCurrentRunAsync( bool obj )
{
    StartTimer();
    PropertyCallBackChangedInstance.PropertyChanged -= PropertyCallBackChangedInstance_PropertyChanged;
    WhenCancelledBlurVolumesGrid = false;
    OriginalTime = SelectedVolumeEstimatedTime();

    return Task.Run( () =>
    {
        CreateEventLogs.WriteToEventLog( string.Format( "Run with Assay:{0} Volume{1} has been started" , SelectedAssay , SelectedVolume ) ,
            LogInformationType.Info );
        var instance = ConnectToInstrument.InstrumentConnectionInstance;
        return instance.InitalizeRun( PopulateRespectiveVolumes() );
    } );
}

private void PropertyCallBackChangedInstance_PropertyChanged( object sender , PropertyChangedEventArgs e )
{
    //bool stepDone = false;
    if ( e.PropertyName == "RunStepStatusName" )
    {
        var value = sender as InstrumentCallBackProperties;
        Dispatcher.CurrentDispatcher.BeginInvoke( ( Action ) ( () =>
        {
            CurrentStatus = value.RunStepStatusName;

            if ( value.RunStepStatusName == "Step5" )
            {
                WorkDone = true;
            }
        } ) );
        //stepDone = true;
    }
}

后台工作人员不更新 UI 并进入无限循环

Background worker doesn't update the UI and goes into an infinite loop

c#

wpf

multithreading

backgroundworker