2.vb串口通信技术文章160rs232串行digitalout的实例

1、代码如下：Imports System.IO.PortsPublic Class Form1 * 表单的Load事件中先将所有的通讯埠先列出来 将通讯埠排序，并将第一个通讯埠设为预设值 * Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load For Each sp As String In SerialPort.GetPortNames() cmbCOM.Items.Add(sp) Next cmbCOM.Sorted = True 排序 c

2、mbCOM.SelectedIndex = 0 第一个是预设选项 btnDTR.Enabled = False btnRTS.Enabled = False End Sub * 开启通讯埠按钮的Click事件 此事件将设定通讯埠参数，并开启通讯埠 * Private Sub btnOpenPort_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOpenPort.Click Dim mPortName As String mPortName = cmbCOM.SelectedItem.To

3、String 欲开启的通讯埠 RS232.PortName = mPortName 指定通讯埠 If Not RS232.IsOpen Then 尚未开启 RS232.Open() 开启通讯埠 RS232.DtrEnable = False RS232.RtsEnable = False picDTR.Image = picOFF.Image picRTS.Image = picOFF.Image btnDTR.Enabled = True btnRTS.Enabled = True Else MsgBox(通讯埠开启错误(通讯埠已被开启), MsgBoxStyle.Critical Or M

4、sgBoxStyle.OkCancel) End End If End Sub * 关闭通讯埠按钮的Click事件 以Cose方法关闭通讯端口，并释放对象所占用的资源 * Private Sub btnClosePort_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClosePort.Click If RS232 Is Nothing OrElse Not RS232.IsOpen Then 尚未开启 MsgBox(通讯埠尚未开启, MsgBoxStyle.Critical Or Ms

5、gBoxStyle.OkCancel) Else RS232.Close() btnDTR.Enabled = False btnRTS.Enabled = False End If End Sub * 结束程序按钮 的Click事件 此事件将设定通讯埠参数，并开启通讯埠 * Private Sub btnEnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEnd.Click If Not RS232 Is Nothing Then 判断是否已建立通讯对象 If RS232.IsOpe

6、n Then RS232.Close() 若已开启，就将其关闭 End If End End Sub * DTR控制按钮 的Click事件 此事件将使得DTR线路状态发生改变 * Private Sub btnDTR_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDTR.Click RS232.DtrEnable = Not RS232.DtrEnable 变更状态 If RS232.DtrEnable Then picDTR.Image = picON.Image 变更为白色图示 El

7、se picDTR.Image = picOFF.Image 变更为红色图示 End If End Sub 更多源码和实例，请关注 (乐 博 网) * RTS控制按钮 的Click事件 此事件将使得RTS线路状态发生改变 * Private Sub btnRTS_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRTS.Click RS232.RtsEnable = Not RS232.RtsEnable 变更状态 If RS232.RtsEnable Then picRTS.Image = picON.Image 变更为白色图示 Else picRTS.Image = picOFF.Image 变更为红色图示 End If End Sub * 通讯埠的KeyPress事件，在此不让使用者输入资料 * Private Sub cmbCOM_KeyPress(ByVal sender As Object, ByVal e