從VB.net 2008中的串行端口讀取信息

Question

我在磚牆上！

我有一個功能性PCB，可通過串行端口報告溫度。

我可以打開超級終端並接收我想要的所有數據-所以我知道設備正在運行...但是我想創建一個VB應用程序，以便可以使用接收到的數據。

當我運行程序時，出現此錯誤：

System.TimeoutException: The operation has timed out.
   at System.IO.Ports.SerialStream.Read(Byte[] array, Int32 offset, Int32 count, Int32 timeout)
   at System.IO.Ports.SerialStream.Read(Byte[] array, Int32 offset, Int32 count)
   at System.IO.Ports.SerialPort.InternalRead(Char[] buffer, Int32 offset, Int32 count, Int32 timeout, Boolean countMultiByteCharsAsOne)
   at System.IO.Ports.SerialPort.ReadTo(String value)
   at System.IO.Ports.SerialPort.ReadLine()
   at Temperature.Form1.ReadFromCom() in C:\Documents and Settings\asamuel\Desktop\VB Project Sollutions\Temperature2\Temperature\Form1.vb:line 43

有人可以幫幫我嗎！ 我快瘋了！

在超級終端中，數據通過這樣的方式來傳遞：

R V1.0 2002-01-06 20:37:37 C
1 0027.00
2 0027.00
3 0027.06
4 0027.18
1 0027.00
2 0027.00
3 0027.06
4 0027.18
1 0027.00
2 0027.06

我的VB應用程式程式碼如下所示：

Imports System
Imports System.IO.Ports
Imports System.Threading

Public Class Form1

    Dim SerialPort1 As New SerialPort
    Dim readThread As Thread = New Thread(AddressOf ReadFromCom)
    Dim abortThread As Boolean

    Public Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Button1.Text Is "Start Capture" Then
            Try
                abortThread = False
                SerialPort1.Open()
                readThread.Start()
                Button1.Text = "Stop Capture"
            Catch ex As Exception
                MsgBox("Another program is already using COM1." & vbCrLf & vbCrLf & _
                       "Please try again later", MsgBoxStyle.OkOnly + MsgBoxStyle.Information, "COM1 Not Available")
            End Try

        ElseIf Button1.Text Is "Stop Capture" Then
            abortThread = True
            Button1.Text = "Start Capture"
        End If
    End Sub

    Public Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        With SerialPort1
            .PortName = "COM1"
            .BaudRate = 2400
            .Parity = Parity.None
            .DataBits = 8
            .StopBits = 1
            .ReadTimeout = 500
        End With
    End Sub

    Public Sub ReadFromCom()
        While abortThread = False
            Try
                Dim message As String = SerialPort1.ReadLine
                updateStatus("Received: " & message)
            Catch ex As TimeoutException
                updateStatus(ex.ToString)
            End Try
        End While            
    End Sub

    Public Delegate Sub updateStatusDelegate(ByVal newStatus As String)
    Public Sub updateStatus(ByVal newStatus As String)
        If Me.InvokeRequired Then
            Dim upbd As New updateStatusDelegate(AddressOf updateStatus)
            Me.Invoke(upbd, New Object() {newStatus})
        Else
            TextBox1.Text = newStatus & vbCrLf & vbCrLf & TextBox1.Text
        End If
    End Sub
End Class

Answer 1

我需要將searialport1.DTREnable設置為true！

現在可以正常工作了-頭痛了2個月了！

Answer 2

您可能希望放棄設計，轉而使用SerialPort-Class的DataReceived-Event（）。

如果到達一定數量的數據（我認為是DataReceivedThreshold-Property），則將觸發DataReceived-Event。 但是該事件將在另一個線程上觸發，因此如果嘗試更改任何控件，請確保使用Invoke（）。

Answer 3

也許這篇文章可以為您提供幫助。 您需要將open語句更改為

...
open "COM1:" for Input as #1
Input #1, MyString
...