无法更新文本框vb.net -crossthreading

Question

我想让应用程序运行多个（adb专用）命令并获取输出并显示在标签中。

首先，我需要启动进程来执行命令。感谢stackoverflow和@pasty我发现这（第二个回复）：How to get Output of a Command Prompt Window line by line in Visual Basic?

嗯，我认为，因为它输出到控制台，它会很简单，只要将它写入标签。大错！它给我一个交叉线程错误！ 谷歌搜索和堆栈溢出一点点，我发现这一点：vb.net accessed from a thread other than the thread it was created on

好了，我想实现这一点，但该程序只是崩溃冻结。

下面是代码：

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 

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

Answer 1

到process.WaitForExit()调用将阻塞UI线程直到衍生的进程退出，但在处理在process.OutputDataReceived事件输出你正在调用Me.Invoke，它试图在被阻塞的UI线程上运行代码，所以程序冻结。您可以将Button1_Click中的逻辑移动到另一个线程上，例如

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

这样的UI线程不会被堵塞，Me.Invoke调用不会导致死锁。