Imports SystemImports System.IO.Ports

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load'获取计算机有效串口        Dim ports As String() = SerialPort.GetPortNames() '必须用命名空间，用SerialPort,获取计算机的有效串口        Dim port As StringFor Each port In ports            portnamebox.Items.Add(port) '向combobox中添加项        Next port'初始化界面        baudratebox.SelectedIndex() = 2        portnamebox.SelectedIndex() = 0        Serial_Port1() '初始化串口        Label3.Text = SerialPort1.IsOpen        statuslabel.Text = "串口未连接"        statuslabel.ForeColor = Color.Red        sendbox.Text = "123"' baudratebox.Text = baudratebox.Items(0) 注释和不注释的地方可以替换        'portnamebox.Text = portnamebox.Items(0)    End Sub

Private Sub Serial_Port1() '设置串口参数        SerialPort1.BaudRate = Val(baudratebox.Text) '波特率        SerialPort1.PortName = portnamebox.Text '串口名称        SerialPort1.DataBits = 8 '数据位        SerialPort1.StopBits = IO.Ports.StopBits.One '停止位        SerialPort1.Parity = IO.Ports.Parity.None '校验位    End Sub

'关闭串口连接    Private Sub closebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles closebtn.ClickTry            SerialPort1.Close() '关闭串口            Label3.Text = SerialPort1.IsOpenIf SerialPort1.IsOpen = False Then                statuslabel.Text = "串口未连接"                statuslabel.ForeColor = Color.Red                receivebox.Text = ""                receivebytes.Text = ""End IfCatch ex As Exception            MessageBox.Show(ex.Message)End TryEnd Sub

'打开串口连接    Private Sub openbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles openbtn.ClickTry            SerialPort1.Open() '打开串口            Label3.Text = SerialPort1.IsOpenIf SerialPort1.IsOpen = True Then                statuslabel.Text = "串口已连接"                statuslabel.ForeColor = Color.GreenEnd IfCatch ex As Exception            MessageBox.Show(ex.Message)End TryEnd Sub

'发送数据    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.ClickTry            SerialPort1.Write(sendbox.Text)Catch ex As Exception            MessageBox.Show(ex.Message)End Try

End Sub

'触发接收事件    Public Sub Sp_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceivedMe.Invoke(New EventHandler(AddressOf Sp_Receiving)) '调用接收数据函数    End Sub

'接收数据    Private Sub Sp_Receiving(ByVal sender As Object, ByVal e As EventArgs)Dim strIncoming As StringTry            receivebytes.Text = Str(Val(receivebytes.Text) + SerialPort1.BytesToRead)If SerialPort1.BytesToRead > 0 Then                Threading.Thread.Sleep(100) '添加的延时                strIncoming = SerialPort1.ReadExisting.ToString '读取缓冲区中的数据                SerialPort1.DiscardInBuffer()                receivebox.Text = strIncomingEnd IfCatch ex As Exception            MessageBox.Show(ex.Message)End TryEnd SubEnd Class