vb.net - 非常基本的 VB.Net 和串行 IO 问题

Question

经过搜索后，我在 VB.Net/VS2010 中从串行端口读取数据时仍然遇到问题。我知道串行端口可以正常工作，我可以很好地写入端口，但从端口读取时，什么也没有发生。我最近 3 周才开始编程，所以我仍在努力理解这一切。

该程序必须运行以从门记录器捕获数据，然后我会将数据输出到数据库(尚未实现 - 我想首先对这部分进行排序)。我尝试使用多个终端程序以及另一个将数据输出到串行线路的设备，但文本框中 tbxIn 中没有显示任何内容。

任何帮助将不胜感激。

代码如下:

Imports System.IO.Ports
Imports System.IO.Ports.SerialPort

Public Class Form1

Dim comPort As IO.Ports.SerialPort = Nothing
Dim sComPort As String = ""
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    GetSerialPortNames()
End Sub

Sub GetSerialPortNames()
    ' Show all available COM ports.
    For Each sp As String In My.Computer.Ports.SerialPortNames
        lstPorts.Items.Add(sp)
    Next
End Sub


Private Sub lstPorts_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstPorts.SelectedIndexChanged
    sComPort = lstPorts.SelectedItem
    Button1.Enabled = True
End Sub

Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    ' Open the serial port using the OpenSerialPort method
    Button1.Enabled = False
    Button2.Enabled = True

    Try
        comPort = My.Computer.Ports.OpenSerialPort(sComPort, 9600, IO.Ports.Parity.None, 8, 1)
        ' comPort.DtrEnable = True
        comPort.ReadTimeout = 500
        Do
            comPort.WriteLine("Go")
            Dim sIncomming As String = comPort.ReadLine()

            tbxIn.Text = sIncomming & vbCrLf
        Loop
    Catch ex As TimeoutException
        tbxIn.Text &= "Error: Serial Port Read Timeout" & vbCrLf
    End Try

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    comPort.Close()
    Button1.Enabled = True
    Button2.Enabled = False
End Sub

Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
    tbxIn.Text = e.ToString
End Sub
End Class

Answer 1

我确信这会满足您的需要。您不需要设计器上的 Serial1 组件。删除它并使用以下代码:

    Private comPort As IO.Ports.SerialPort = Nothing
Private sComPort As String = ""

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)
    GetSerialPortNames()
End Sub

Sub GetSerialPortNames()


    ' Show all available COM ports.    
    For Each sp As String In My.Computer.Ports.SerialPortNames
        lstPorts.Items.Add(sp)
    Next
End Sub

Private Sub lstPorts_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstPorts.SelectedIndexChanged
    sComPort = lstPorts.SelectedItem
    Button1.Enabled = True
End Sub

Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click


    ' Open the serial port using the OpenSerialPort method    
    Button1.Enabled = False
    Button2.Enabled = True
    Try


        comPort = My.Computer.Ports.OpenSerialPort(sComPort, 9600, IO.Ports.Parity.None, 8, 1)
        ' comPort.DtrEnable = True      

        'must add handler
        AddHandler comPort.DataReceived, AddressOf SerialPort1_DataReceived

        comPort.ReadTimeout = 500
        Do
            comPort.WriteLine("Go")
            Dim sIncomming As String = comPort.ReadLine()
            tbxIn.Text = sIncomming & vbCrLf
        Loop
    Catch ex As TimeoutException
        tbxIn.Text &= "Error: Serial Port Read Timeout" & vbCrLf
    End Try
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    comPort.Close()
    'remove handler
    RemoveHandler comPort.DataReceived, AddressOf SerialPort1_DataReceived
    Button1.Enabled = True
    Button2.Enabled = False
End Sub
Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs)
    tbxIn.Text = e.ToString
End Sub