imports system
imports 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 string
        for 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.click
        try
            serialport1.close() '关闭串口
            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
            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


    '发送数据
    private sub button1_click(byval sender as system.object, byval e as system.eventargs) handles button1.click
        try
            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.datareceived
        me.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 string
        try
            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 = strincoming
            end if
        catch ex as exception
            messagebox.show(ex.message)
        end try
    end sub
end class