VB2005中SerialPort基本操作源代码

示例代码功能有：搜索全部串口，搜索可用串口，串口打开与关闭，字符串发送，字符串中断接收。发送接收用的是同一串口，测试时端接串口2、3脚即可。中断接收时无法直接显示收到字符（涉及到跨线程问题），用了个定时器定时刷新显示收到的字符串。
程序界面：

程序代码：
imports system
imports system.io.ports         使用serialport所引用的命名空间
imports system.threading        使用thread所引用的命名空间
public class form1
   dim strrec as string        接收字符串
   dim strsend as string       发送字符串
   dim intnum as integer       接收字节数=字符数+1（vblf）
   private sub button1_click(byval sender as system.object, byval e as system.eventargs) handles button1.click
       combobox1.items.clear() 清空列表
       combobox2.items.clear()
       for each portname as string in my.computer.ports.serialportnames
           combobox1.items.add(portname)           显示所有串口
           try
               serialport1.portname = portname
               serialport1.open()
               combobox2.items.add(portname)       显示可用串口
               serialport1.close()
           catch ex as exception
               msgbox(可用串口检查 & portname)
           end try
       next
       if combobox1.items.count > 0 then combobox1.selectedindex = 0
       if combobox2.items.count > 0 then
           combobox2.selectedindex = 0
           button2.enabled = true          有可用串口，可以打开操作
       end if
   end sub
 
   private sub button2_click(byval sender as system.object, byval e as system.eventargs) handles button2.click
       if button2.text = 打开串口 then
           serialport1.portname = combobox2.text
           if not serialport1.isopen then
               serialport1.open()
               button2.text = 关闭串口
               button3.enabled = true      串口打开，可以发送数据
           end if
       else
           if serialport1.isopen then serialport1.close()
           button2.text = 打开串口
           button3.enabled = false
       end if
   end sub
   private sub button3_click(byval sender as system.object, byval e as system.eventargs) handles button3.click
       strsend = textbox1.text
       serialport1.writeline(strsend)
   end sub
   中断接收字符串
   private sub serialport1_datareceived(byval sender as object, byval e as system.io.ports.serialdatareceivedeventargs) handles serialport1.datareceived
       thread.sleep(100)                   根据字符数量及波特率计算延时
       intnum = serialport1.bytestoread
       strrec = serialport1.readline
   end sub
   关闭程序时关闭串口
   private sub form1_formclosing(byval sender as object, byval e as system.windows.forms.formclosingeventargs) handles me.formclosing
       if serialport1.isopen then serialport1.close()
   end sub
   定时更新显示接收字符串
   private sub timer1_tick(byval sender as system.object, byval e as system.eventargs) handles timer1.tick
       textbox2.text = strrec
       textbox3.text = intnum
   end sub
end class
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原文地址： Http://blog.gkong.com/more.asp?id=131982&Name=zhouchs