带有串口的vb.net中的跨线程操作无效 [英] Cross-thread operation not valid in vb.net with serial port

问题描述

我有一个表单，它使用一个类来处理富文本框中的传入数据.数据通过串口接收.

I have a form that uses a class to process incoming data in a richtextbox. The data is received via serial port.

当我加载表单时，我通过这样做来初始化类:

When I load the form I initialize the class by doing this:

oDigi = New DigitalProcessing
oDigi.InitHostForm(Me, 1, MyParentNumber)

并在类中执行此操作:

Public Sub InitHostForm(ByVal theHostForm As Object, ByVal iInterface As Integer,      Optional ByVal Parent As Integer = 0)
Hostform = theHostForm
ParentNr = Parent
End Sub

在表单中，我初始化了串行端口，一切都很好.当从串行端口接收到文本时，调用此例程:

In the form I initialize the serialport and everything is good. When text is received from the serial port this routine is called:

Private Sub MSComm1_DataReceived(sender As Object, e As SerialDataReceivedEventArgs) Handles MSComm1.DataReceived
    If Unloaded Then Exit Sub
    oDigi.RxComData(MSComm1.ReadExisting, Val(MyRXid))
End Sub

这就是调用这个例程:

Public Sub PrintToRxWindow(ByVal sMsg As String, ByVal Index As Integer)
If Len(Hostform.rtfRX(Index).Text) > lMaxLen Then
LockWindowUpdate(Hostform.rtfRX(Index).Handle)
Hostform.rtfRX(Index).SelectionStart = 0
Hostform.rtfRX(Index).SelectionLength = 500
Hostform.rtfRX(Index).ReadOnly = False
Hostform.rtfRX(Index).SelectedText = ""
Hostform.rtfRX(Index).ReadOnly = True
LockWindowUpdate(0)
End If

在上面的 If 行中，我收到以下错误跨线程操作无效:Control '' 从创建它的线程以外的线程访问."

In the If line above I get the following error "Cross-thread operation not valid: Control '' accessed from a thread other than the thread it was created on."

这仅在我使用串行端口时发生.如果我通过另一种方法输入文本，则不会出现错误.在 Microsoft 上进行一些搜索后，我发现串行端口类将在它自己的线程中运行，因此我了解单独的线程来自何处.但我不知道如何解决它.我猜我需要使用 .invoke 但我不知道需要在哪里完成.

This only happens if I use the serial port. If I input text via another method then I do not get an error. Upon doing some searching on Microsoft I found that the Serial port class will run in it's own thread so I understand where the separate threads are coming from. But I do not know how to fix it. I am guessing I need to use .invoke but I can't figure out where it needs to be done.

推荐答案

那是因为 DataReceived 事件是从帮助线程返回的.使用委托:

That is because the DataReceived event is returned from a helper thread. Use a delegate:

Private Sub MSComm1_DataReceived(sender As Object, e As SerialDataReceivedEventArgs) Handles MSComm1.DataReceived
 If Unloaded Then Exit Sub
 'lambda sub acting as delegate
 'all code inside this sub is on UI thread
 Me.Invoke(Sub()
            oDigi.RxComData(MSComm1.ReadExisting, Val(MyRXid))
           End Sub)
End Sub

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