学习VB.net串口发送与接收(二)

最新推荐文章于 2025-07-27 09:28:40 发布

转载最新推荐文章于 2025-07-27 09:28:40 发布 · 3.3k 阅读

本文介绍了一个使用VB.NET实现串口通信的例子程序。该程序通过创建串口实例并设置波特率、数据位等参数来初始化串口，并提供发送和接收数据的功能。此外，还实现了串口状态监测及定时读取数据。

Imports System.IO.Ports
Imports System.Text

Public Class Form1
    Dim WithEvents Rs232 As SerialPort
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        For Each a As String In SerialPort.GetPortNames()
            CmbCom.Items.Add(a)
        Next
        CmbCom.SelectedIndex = 0
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim mPortName As String
        Dim mBuandBit As Integer
        Dim mDataBit As Integer
        Dim mStopBit As IO.Ports.StopBits
        Dim mParityBit As IO.Ports.Parity
        mPortName = CmbCom.SelectedItem.ToString
        mBuandBit = 9600
        mDataBit = 8
        mStopBit = StopBits.One
        mParityBit = Parity.None
        Rs232 = New SerialPort(mPortName, mBuandBit, mParityBit, mDataBit, mStopBit)
        If Not Rs232.IsOpen Then
            Rs232.Open()
            btnSend.Enabled = True
            Timer1.Interval = 100
            Timer1.Enabled = True
            MsgBox("~~通讯端口打开成功！~~", MsgBoxStyle.OkCancel)
        Else
            MsgBox("~~通讯端口打开失败（通讯端口已打开）~~", MsgBoxStyle.OkCancel)
        End If
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        Dim Inbyte() As Byte, ReadCount As Integer
        If Rs232.BytesToRead <= 0 Then Exit Sub
        ReDim Inbyte(Rs232.BytesToRead - 1)
        ReadCount = Rs232.Read(Inbyte, 0, Rs232.BytesToRead)
        If ReadCount = 0 Then
            Exit Sub
        Else
            For Each bData As Byte In Inbyte
                txtReceive.Text += bData.ToString & vbCrLf
            Next
        End If
    End Sub

    Private Sub btnClose_Click(sender As Object, e As EventArgs) Handles btnClose.Click
        If Rs232 Is Nothing OrElse Not Rs232.IsOpen Then
            MsgBox("~~通讯端口尚未打开~~", MsgBoxStyle.Critical Or MsgBoxStyle.OkCancel)
        Else
            btnSend.Enabled = False
            Timer1.Enabled = False
            Rs232.Close()
        End If
    End Sub

    Private Sub btnEnd_Click(sender As Object, e As EventArgs) Handles btnEnd.Click
        If Not Rs232 Is Nothing Then
            If Rs232.IsOpen Then Rs232.Close()
        End If
    End Sub

    Private Sub btnSend_Click(sender As Object, e As EventArgs) Handles btnSend.Click
        Dim bDataOut(0) As Byte
        Try
            bDataOut(0) = CType(txtSend.Text, Byte) '文本中输入0-255的数字
            Rs232.Write(bDataOut, 0, 1)
        Catch ex As Exception
            MsgBox(ex.Message.ToString(), MsgBoxStyle.OkCancel)
        End Try
    End Sub
End Class