VB.net简单多线程 [英] VB.net Simple Multithreading

问题描述

我有一个Private Sub Fill()，我试图从button1以

I have a Private Sub Fill(), which im trying to call from button1, in the form of

Dim t1 As System.Threading.Thread = New System.Threading.Thread(AddressOf Me.Fill)

t1.Start()

但是，当我运行程序时，什么也没发生.我多次单击该按钮，但该功能未执行.是什么赋予了? Fill函数基本上是从IE将一堆html输出到文本框中，运行正则表达式并将结果输出到列表框中.

However, when I run the program nothing happens. I click the button numerous times and the function isnt being executed. What gives? The Fill function is basically a outputting bunch of html from IE into a textbox, running regex and outputting the results in a listbox.

有人可以帮助我完成这项工作吗?非常感谢您的帮助. 编辑:下面是我要开始使用的Fill函数.当我尝试不使用多线程时，该函数本身可以工作.但是没有...

Can anyone help me get this working? I'd appreciate the help. Below, is the Fill function that I am trying to get working. The function itself works, when i try it without multithreading. But not with it...

Private Sub Fill()
    Try
        For Each links In ListBox2.Items
            Dim blah As Boolean = False
            Do While blah = False
                Application.DoEvents()
                If WebBrowser1.ReadyState = WebBrowserReadyState.Complete Then
                    blah = True
                    WebBrowser1.Navigate(links)
                    Application.DoEvents()
                    Me.Refresh()
                    'OUTPUT THE REGEX IN RTB
                    Try
                        RichTextBox1.Text = WebBrowser1.Document.Body.OuterHtml
                        RichTextBox1.Update()
                        Application.DoEvents()
                        Me.Refresh()
                        'INTRODUCE REGEX
                        If CheckBox1.Checked = True Then
                            Dim R As New Regex("</H3>&lt;.*gt;")
                            For Each M As Match In R.Matches(RichTextBox1.Text)
                                Dim email As String = M.Value.Substring(9).Split("&;").GetValue(0).ToString
                                ListBox1.Items.Add(email)
                            Next
                        End If
                    Catch ex As Exception
                        Label1.Text = "Error recieved. Program will not stop"
                        Me.Refresh()
                    End Try
                    Application.DoEvents()
                    Me.Refresh()
                End If
            Loop
        Next
    Catch ex As Exception

    End Try
End Sub

推荐答案

我认为您遇到了问题，因为当您尝试在Fill()方法中写入文本框时，您不在UI线程上–这将导致一个例外.要解决该问题，您需要使用 BeginInvoke 和一个委托切换到UI线程，如下例所示:

I think you are having problems because you are not on the UI thread when you are trying to write to the textbox in the Fill() method – this will causes an exception. To solve the problem you need to switch to the UI thread using BeginInvoke and a delegate as in the example below:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim t1 As System.Threading.Thread = New System.Threading.Thread(AddressOf Me.Fill)
        t1.Start()

End Sub

Private Delegate Sub FillDelegate()

Private Sub Fill()
        If TextBox1.InvokeRequired Then
            TextBox1.BeginInvoke(New FillDelegate(AddressOf Fill))
        Else
            TextBox1.Text = "Worked!!!!"
        End If
End Sub

这篇关于VB.net简单多线程的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！