VS2010环境下使用VB编写串口助手

1、在Form1的设计模式下添加以下控件：

2、添加好控件之后我们就可以打开Form1.vb进行编程了：

'使用串口需要引用的命名空间
Imports System.IO.Ports
Imports System


Public Class Form1

  

    '在设计视图中双击Form1窗体出现的函数，在第一次显示窗体前发生的事件写在这个里面，类似于ViewWillAppear
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        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 String

        For Each port In ports
            portnamebox.Items.Add(port) '向combobox中添加项
        Next

        '初始化界面
        baudratebox.Text = baudratebox.Items(2) '注释和不注释的地方可以替换
        portnamebox.Text = portnamebox.Items(0)
        '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"
        receivebytes.Text = "0"
        linecheck.Enabled = True
        timebox.Enabled = True

        '让发送、接收数据按钮不能点击（失能）
        Button1.Enabled = False
        Button2.Enabled = False
        Button3.Enabled = False




    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.PortName = portnamebox.SelectedItem
        SerialPort1.BaudRate = Val(baudratebox.SelectedItem)
        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.Click
        Try
            SerialPort1.Close() '关闭串口

            '让发送、接收数据按钮不能点击（失能）
            Button1.Enabled = False
            Button2.Enabled = False
            Button3.Enabled = False

            Label3.Text = SerialPort1.IsOpen
            If SerialPort1.IsOpen = False Then
                statuslabel.Text = "串口未连接"
                statuslabel.ForeColor = Color.Red
                receivebox.Text = ""
                receivebytes.Text = ""
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub


    '打开串口连接
    Private Sub openbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles openbtn.Click
        Try
            SerialPort1.Open() '打开串口
            timebox.Enabled = True
            '使能按钮
            Button1.Enabled = True
            Button2.Enabled = True
            Button3.Enabled = True


            Label3.Text = SerialPort1.IsOpen
            If SerialPort1.IsOpen = True Then
                statuslabel.Text = "串口已连接"
                statuslabel.ForeColor = Color.Green
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub



    '手动发送数据
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        send()
    End Sub


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



    '接收数据过程
    Private Sub Sp_Receiving(ByVal sender As Object, ByVal e As EventArgs)

        ' Dim strIncoming As Byte
        Dim strIncoming As Integer
        Dim str1() As String
        Dim str2() As String
        Dim bytes() As Byte
        Dim i As Integer
        Try
            Threading.Thread.Sleep(100) '添加的延时
            ' receivebytes.Text = Str(Val(receivebytes.Text) + SerialPort1.BytesToRead)
            receivebytes.Text = Str(SerialPort1.BytesToRead)

            If SerialPort1.BytesToRead > 0 Then

                ReDim bytes(SerialPort1.BytesToRead)
                'strIncoming = Convert.ToByte(SerialPort1.ReadByte())
                If receivecheck.Checked = True Then
                    strIncoming = SerialPort1.ReadByte()
                    bytes(0) = strIncoming
                    For i = 1 To SerialPort1.BytesToRead
                        strIncoming = SerialPort1.ReadByte() '读取缓冲区中的数据
                        bytes(i) = strIncoming
                    Next
                    ' SerialPort1.Write(sendbox.Text)'发送数据
                    SerialPort1.DiscardInBuffer()
                    str1 = Split(BitConverter.ToString(bytes), "-")

                    ReDim str2(str1.Length - 1) '去除str1中最后的字符
                    For i = 0 To str1.Length - 2
                        str2(i) = str1(i)
                    Next
                    receivebox.Text = receivebox.Text & Join(str2, " ")
                    'BitConverter.ToString(bytes)
                Else
                    receivebox.Text = receivebox.Text & SerialPort1.ReadExisting()
                End If

            End If
            
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub

    Public Sub send() '发送数据过程
        Dim databyte() As Byte
        Dim str1() As String
        Dim str2 As String
        Dim str3 As String
        Dim i As Integer

        Try
            If sendcheck.Checked = False Then '不按照16进制发送
                'timecheck.Enabled = True

                If linecheck.Checked = False Then '判断是否选中分行发送
                    SerialPort1.Write(sendbox.Text)
                Else
                    SerialPort1.WriteLine(sendbox.Text)
                End If

            Else '按照16进制发送
                If InStr(sendbox.Text, " ") Then '判断是否有空格
                    str1 = Split(sendbox.Text)
                    str2 = Join(str1, "")
                Else
                    str2 = sendbox.Text
                End If

                If str2.Length Mod 2 = 0 Then '判断字符串字节数是否为偶数
                    ReDim databyte(str2.Length / 2) '重新定义数组
                    For i = 0 To str2.Length / 2 - 1
                        databyte(i) = Convert.ToByte(Mid(str2, 2 * i + 1, 2), 16) '两个字符转换为一个16进制字节
                        'databyte(i) = Val(Mid(str2, 2 * i + 1, 2))
                    Next
                    SerialPort1.Write(databyte, 0, databyte.Length - 1)
                    sendbytes.Text = Str(Val(sendbytes.Text) + databyte.Length - 1)
                Else

                    str3 = Mid(str2, 1, (str2.Length - 1)) & "0" & Mid(str2, str2.Length)
                    ReDim databyte(str3.Length / 2)
                    For i = 0 To str3.Length / 2 - 1
                        databyte(i) = Convert.ToByte(Mid(str3, 2 * i + 1, 2), 16)
                    Next
                    SerialPort1.Write(databyte, 0, databyte.Length - 1)
                    sendbytes.Text = Str(Val(sendbytes.Text) + databyte.Length - 1)
                End If
                'databyte = System.Text.Encoding.Default.GetBytes(sendbox.Text)把每个字符转换成字节

            End If

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try

    End Sub

    '更改串口设置
    Private Sub portnamebox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles portnamebox.SelectedIndexChanged
        Try
            Serial_Port1()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
   
    '清空发送区数据
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        sendbox.Text = ""
    End Sub

    '清空接收区数据
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        receivebox.Text = ""
        receivebytes.Text = 0

    End Sub

    '定时发送数据
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer1.Interval = timebox.Text
        send()
    End Sub

    '选择定时发送的触发事件
    Private Sub timecheck_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles timecheck.CheckedChanged

        If timecheck.Checked = True Then
            If timebox.Text = "" Then
                MsgBox("时间间隔不能为0")
                timecheck.Checked = False
            Else
                send()
                timebox.Enabled = False
            End If
        Else
            timebox.Enabled = True
        End If
    End Sub




    
    
End Class

然后运行，由于我电脑上没有串口，所以使用usb转串口线，这个线所用的转换芯片是ch340。

安装好驱动之后在计算机管理中查是COM3.

然后把串口的2,3针脚用杜邦线短路，因为这样的话我用电脑发送后又可以用电脑的同一个串口接收数据，方便测试。

测试效果如下：