BackgroundWorker'DoWork'事件沒有觸發

我有一個加載得很好的表單，而且我試圖在加載時使用後臺工作器來觸發一個任務。BackgroundWorker'DoWork'事件沒有觸發

我沒有收到下面的代碼錯誤，但bw.DoWork事件似乎並沒有被解僱。

我在這裏錯過了什麼嗎？謝謝。

這裏是我的表單類 -

Public Class mainForm 

    Dim objWorker As MyWorker 

    Private Sub mainForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
     Call Me.loadForm() 
    End Sub 

    Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click 
     Call Me.closeForm() 
    End Sub 

    Private Sub loadForm() 

     Me.objWorker = New MyWorker ' Invoke the background worker 

    End Sub 

    Private Sub closeForm() 

     Me.objWorker.bw_Cancel() ' Cancel the background worker 
     Me.Close()     ' Close the form 

    End Sub 

End Class

這裏是我的BackgroundWorker類 -

Imports System.ComponentModel 

Partial Public Class MyWorker 

    Private bw As BackgroundWorker = New BackgroundWorker 

    Public Sub New() 

     bw.WorkerReportsProgress = False 
     bw.WorkerSupportsCancellation = True 
     AddHandler bw.DoWork, AddressOf bw_DoWork 
     AddHandler bw.RunWorkerCompleted, AddressOf bw_RunWorkerCompleted 

    End Sub 

    Private Sub bw_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs) 

     Dim worker As BackgroundWorker = CType(sender, BackgroundWorker) 
     For i = 1 To 10 
      If bw.CancellationPending = True Then 
       e.Cancel = True 
       Exit For 
      Else 
       System.Threading.Thread.Sleep(500) 
       MsgBox("iteration " & i) 
      End If 
     Next 

    End Sub 

    Private Sub bw_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) 
     MsgBox("Complete!") 
    End Sub 

    Public Sub bw_Cancel() 
     If bw.WorkerSupportsCancellation = True Then 
      bw.CancelAsync() 
     End If 
    End Sub 

End Class

來源

2013-12-11 David Gard

所有你做的是創造它。您忘記調用RunWorker方法 – Plutonix

缺少對RunWorkerAsync的調用，但請[請檢查此q/a]（http://stackoverflow.com/questions/1731384/how-to-stop-backgroundworker-on-forms -closing-event），當表單關閉時，你可能會遇到運行的BackgroundWorker問題 – Steve

@Steve - 謝謝。現在還不早，但我打算確保在表單關閉時BackgroundWorker不活動。 –

添加到MyWorker構造函數（ '新' 的方法）這一行：

bw.RunWorkerAsync()

來源

2013-12-11 16:42:37 dovid

啊，是的，我現在在文檔中看到它。謝謝，那確實是問題所在。 –

BackgroundWorker'DoWork'事件沒有觸發

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