2.vb串口通信技术文章160rs232串行looptest的实例

1、代码如下：Imports System.IO.PortsImports System.TextPublic Class Form1*窗体的Load 事件中先将所有的通信端口先列出来将通信端口排序，并将第一个通信端口设为默认值*Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesMyBase.LoadFor Each sp As String In SerialPort.GetPortNames.Items.Add(sp)Next.Sorted = True 排序.Se

2、lectedIndex = 0 第一个是默认选项End Sub*打开通信端口按钮的Click 事件此事件将设定通信端口参数，并打开通信端口*Private Sub btnOpenPort_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesbtnOpenPort.ClickDim mPortName As StringmPortName =.SelectedItem.ToString 欲打开的通信端口RS232.PortName = mPortNameRS232.Encoding = Encoding

3、.ASCIIIf Not RS232.IsOpen Then 还未打开RS232.Open() 打开通信端口btnSend.Enabled = True 致能传送按钮btnReceive.Enabled = TrueElseMsgBox(通信端口打开错误(通信端口已被打开), MsgBoxStyle.Critical OrMsgBoxStyle.OkCancel)EndEnd If vb net 源码和实例，请关注(乐 博 网)End Sub*传送按钮的Click 事件将文字框中的文字以 Write 方法自串行端口送出*Private Sub btnSend_Click(ByVal sende

4、r As System.Object, ByVal e As System.EventArgs) HandlesbtnSend.ClickRS232.Write(txd.Text & vbCr)End Sub*接收按钮的Click 事件以ReadExisting 方法自串行端口数据*Private Sub btnReceive_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesbtnReceive.ClickDim InString As StringInString = TryRS232.Read

5、Timeout = 1000InString = RS232.ReadExisting()If InString Is Nothing ThenExit SubElsetxtReceive.Text = InStringEnd IfCatch ex As ExceptionMessageBox.Show(错误： + ex.ToString, 错误通知, MessageBoxButtons.OK,MessageBoxIcon.Exclamation)End TryEnd Sub*关闭通信端口按钮的Click 事件以Cose 方法关闭通信端口，并对象所占用的资源*Private Sub btnCl

6、ose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesbtnClose.ClickIf RS232 Is Nothing OrElse Not RS232.IsOpen Then 还未打开MsgBox(通信端口还未打开, MsgBoxStyle.Critical Or MsgBoxStyle.OkCancel)ElseRS232.Close()btnSend.Enabled = FalsebtnReceive.Enabled = FalseEnd IfEnd Sub*结束程序按钮的Click 事件此事件将设定通信端口参数，并打开通信端口*Private Sub btnEnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesbtnEnd.ClickIf Not RS