Question

在我的WPF 3.5应用程序中使用BackGroundWorker使一个长时间运行的进程在自己的线程上运行，当我在VS2010中以调试模式运行代码时，DoWork和RunWorkerCompleted事件似乎没有被触发。

我的代码如下：

Implements INotifyPropertyChanged  

Private WithEvents worker As System.ComponentModel.BackgroundWorker  

Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

Private Sub NotifyPropertyChanged(ByVal info As String)
  RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
End Sub

Private Sub Window_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
  Dim worker = New System.ComponentModel.BackgroundWorker
  worker.WorkerReportsProgress = True
  worker.WorkerSupportsCancellation = True
  Dim str() = New String() {"IDA00005.dat", "Adelaide"}
  Try
    worker.RunWorkerAsync(str)
  Catch ex As Exception
    MsgBox(ex.Message)
  End Try
End Sub

Private Sub worker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles worker.DoWork
  Dim form_Helpder As New test_global
  Dim ds As DataSet = form_Helpder.getWeatherData(e.Argument(0), e.Argument(1))
  e.Result = ds
End Sub

Private Sub worker_Completed(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) Handles worker.RunWorkerCompleted
  If e.Error IsNot Nothing Then
    MsgBox(e.Error.Message)
  Else
    ...
    NotifyPropertyChanged("lbl_minToday")
    ...
  End If
End Sub

我在runworkerasync上设置断点并调用该行，而不是捕获错误但是sub已经结束。我在DoWork和RunWorkerCompleted子上也设置了断点，在Window_Loaded子结束后，调试器没有突出显示任何其他内容，所以我只假设事件没有被触发。

我有两个问题，我的代码中是否有什么东西会导致事件无法触发，是否使用在Event subs上设置的断点是正确的调试方式？

我们将非常感谢您提供的任何帮助。

马特

Answer 1

DoWork和worker_Completed是事件。您必须将它们注册到工作人员的事件处理程序，以便工人解雇它们。

worker.DoWork += worker_DoWork
worker.RunWorkerCompleted += worker_Completed

编辑：在VB中，语法如下：

AddHandler worker.DoWork, AddressOf worker_DoWork
AddHandler worker.RunWorkerCompleted, AddressOf worker_Completed

关于你的第二个问题，是的，如果在worker子例程上设置断点，调试器将会中断。 DoWork在后台ThreadPool线程上运行，而RunWorkerCompleted被引发并在UI线程上运行（这使得backgroundWorkers如此有用。）

BackgroundWorker事件未触发

1 个答案: