VB.net将值设置为backgroundworker中的标签

Question

我的代码有效,但我怀疑我做了什么,因为我将CheckForIllegalCrossThreadCalls设置为false,我认为这会给我的后台工作者带来一些副作用.这是我的示例代码:

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = False

End Sub

Private Sub go_Click(sender As Object, e As EventArgs) Handles go.Click

    Try
        If BackgroundWorker1.IsBusy <> True Then
            BackgroundWorker1.RunWorkerAsync()
            resetevent.Set()
        End If

    Catch ex As Exception

    End Try

End Sub


Private Sub BackgroundWorker1_DoWork(sender As System.Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork

    Do

    Label1.Text = x
Label2.Text = Label1.Text
Label3.Text = Label2.Tex
Label4.Text = Label3.Text
Label5.Text = Label4.Text

    x+=1
    Loop While (x < 100)


End Sub

Private Sub BackgroundWorker1_ProgressChanged(sender As System.Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
    Try



    Catch ex As Exception

    End Try
End Sub

Private Sub BackgroundWorker1_Completed(sender As System.Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted

    Try

    Catch ex As Exception

    End Try
End Sub

有没有办法在不将CheckForIllegalCrossThreadCalls设置为False的情况下将值设置为backgroundworker中的标签？因为我的程序遇到了一些错误,即使尚未达到计数器限制,循环也会突然停止.

Answer 1

创建方法

  Private Sub setLabelTxt(ByVal text As String, ByVal lbl As Label)
    If lbl.InvokeRequired Then
        lbl.Invoke(New setLabelTxtInvoker(AddressOf setLabelTxt), text, lbl)
    Else
        lbl.Text = text
    End If
End Sub
Private Delegate Sub setLabelTxtInvoker(ByVal text As String, ByVal lbl As Label)

并在DoWork中调用setLabelTxt.

编辑: 我稍后会在参考文献中添加解释,因为我现在有点忙.我也有你的问题,这对我有用.

编辑:

" 从工作线程安全访问控件的方法是通过委托. 首先测试控件的InvokeRequired属性,它将告诉您是否可以安全地访问控件.InvokeRequired是Control类的少数几个成员之一是线程安全的,所以你可以在任何地方访问它.如果属性为True,则需要调用来访问控件,因为当前方法在拥有控件的Handle的线程以外的线程上执行.

通过调用控件的Invoke或BeginInvoke方法来执行调用.您创建一个委托,该委托是一个包含对方法的引用的对象.最好将其作为对当前方法的引用.然后,您将该委托传递给Invoke或BeginInvoke方法.这将基本上再次调用引用的方法,这次是在拥有控件的Handle的线程上."

来源:jmcilhinney发布工作线程访问控件 http://www.vbforums.com/showthread.php?498387-Accessing-Controls-from-Worker-Threads

我不能比他更好地解释,因为我也是一个菜鸟