無法更新文本框vb.net -crossthreading

Question

我想讓應用程序運行多個（adb專用）命令並獲取輸出並顯示在標籤中。

首先，我需要啓動進程來執行命令。感謝stackoverflow和@pasty我發現這（第二個回覆）：How to get Output of a Command Prompt Window line by line in Visual Basic?

嗯，我認爲，因爲它輸出到控制檯，它會很簡單，只要將它寫入標籤。大錯！它給我一個交叉線程錯誤！ 谷歌搜索和堆棧溢出一點點，我發現這一點：vb.net accessed from a thread other than the thread it was created on

好了，我想實現這一點，但該程序只是崩潰凍結。

下面是代碼：

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    ' store error output lines 

    Dim executable As String() = {"adb", "adb"} 
    Dim arguments As String() = {"help", "reboot"} 
    For i As Integer = 0 To 0 
     Dim process = New Process() 
     process.StartInfo = createStartInfo(executable(i), arguments(i)) 
     process.EnableRaisingEvents = True 
     AddHandler process.Exited, Sub(ByVal sendera As Object, ByVal ea As System.EventArgs) 
             Console.WriteLine(process.ExitTime) 
             Console.WriteLine(". Processing done.") 
             'UpdateTextBox(ea) 

            End Sub 
     ' catch standard output 
     AddHandler process.OutputDataReceived, Sub(ByVal senderb As Object, ByVal eb As DataReceivedEventArgs) 
                If (Not String.IsNullOrEmpty(eb.Data)) Then 
                 Console.WriteLine(String.Format("{0}> {1}", DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss"), eb.Data)) 
                 'UpdateTextBox(eb.Data) 

                End If 
               End Sub 
     ' catch errors 
     AddHandler process.ErrorDataReceived, Sub(ByVal senderc As Object, ByVal ec As DataReceivedEventArgs) 
                Console.WriteLine(String.Format("! {0}", ec.Data)) 
                Dim a As String = String.Format("! {0}", ec.Data) 
                'UpdateTextBox(a) 
               End Sub 
     ' start process 
     Dim result = process.Start() 
     ' and wait for output 
     process.BeginOutputReadLine() 
     ' and wait for errors :-) 
     process.BeginErrorReadLine() 
     process.WaitForExit() 

    Next 

End Sub 

Private Sub UpdateTextBox(ByVal a As String) 
    If Me.InvokeRequired Then 
     Dim args() As String = {a} 
     Me.Invoke(New Action(Of String)(AddressOf UpdateTextBox), args) 
     Return 
    End If 
    Label1.Text += "a" 
End Sub 

Private Function createStartInfo(ByVal executable As String, ByVal arguments As String) As ProcessStartInfo 
    Dim processStartInfo = New ProcessStartInfo(executable, arguments) 
    processStartInfo.WorkingDirectory = Path.GetDirectoryName(executable) 
    ' we want to read standard output 
    processStartInfo.RedirectStandardOutput = True 
    ' we want to read the standard error 
    processStartInfo.RedirectStandardError = True 
    processStartInfo.UseShellExecute = False 
    processStartInfo.ErrorDialog = False 
    processStartInfo.CreateNoWindow = True 
    Return processStartInfo 

End Function 

和源代碼：https://github.com/iAmAOpenSource/SyncfusionWindowsFormsApplication3

Answer 1

到process.WaitForExit()調用將阻塞UI線程直到衍生的進程退出，但在處理在process.OutputDataReceived事件輸出你正在調用Me.Invoke，它試圖在被阻塞的UI線程上運行代碼，所以程序凍結。您可以將Button1_Click中的邏輯移動到另一個線程上，例如

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    Task.Run(
     Sub() 
      ... current logic 
     End Sub 
    ) 
End Sub 

這樣的UI線程不會被堵塞，Me.Invoke調用不會導致死鎖。