2010-05-09 2:22
VB.Net RS232串行通信AutoReceive的實(shí)例
VB.Net RS232串行通信AutoReceive的實(shí)例
代碼如下：
Imports System.IO.Ports
Imports System.Text
Public Class Form1
'聲明一個(gè)委派類(lèi)，并聲明符合函數(shù)參數(shù)有一個(gè)，而其類(lèi)型是字符串
Delegate Sub SetTextCallback(ByVal InputString As String)
'**************************************************************
'窗體的Load事件中先將所有的通信端口先列出來(lái)
'將通信端口排序，并將第一個(gè)通信端口設(shè)為默認(rèn)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
cmbCOM.SelectedIndex = 0 '第一個(gè)是默認(rèn)選項(xiàng)
End Sub
'**************************************************************
'『打開(kāi)通信端口』按鈕的Click事件
'此事件將設(shè)定通信端口參數(shù)，并打開(kāi)通信端口
'**************************************************************
Private Sub btnOpenPort_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOpenPort.Click
Dim mPortName As String
mPortName = cmbCOM.SelectedItem.ToString '欲打開(kāi)的通信端口
RS232.PortName = mPortName
RS232.Encoding = Encoding.ASCII
If Not RS232.IsOpen Then '還未打開(kāi)
RS232.Open() '打開(kāi)通信端口
Else
MsgBox("~~通信端口打開(kāi)錯(cuò)誤(通信端口已被打開(kāi))~~", MsgBoxStyle.Critical Or MsgBoxStyle.OkCancel)
End
End If
End Sub
'**************************************************************
'『關(guān)閉通信端口』按鈕的Click事件
'以Cｌose方法關(guān)閉通信端口，并釋放對(duì)象所占用的資源
'**************************************************************
Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
If RS232 Is Nothing OrElse Not RS232.IsOpen Then '還未打開(kāi)
MsgBox("~~通信端口還未打開(kāi)~~", MsgBoxStyle.Critical Or MsgBoxStyle.OkCancel)
Else
RS232.Close()
End If
End Sub
'**************************************************************
'『結(jié)束程序』按鈕的Click事件
'此事件將設(shè)定通信端口參數(shù)，并打開(kāi)通信端口
'**************************************************************
Private Sub btnEnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEnd.Click
If Not RS232 Is Nothing Then '判斷是否已創(chuàng)建通信對(duì)象
If RS232.IsOpen Then RS232.Close() '若已打開(kāi)，就將其關(guān)閉
End If
End
End Sub
'**************************************************************
'通信端口的KeyPress事件，在此不讓用戶(hù)輸入數(shù)據(jù)
'**************************************************************
Private Sub cmbCOM_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles cmbCOM.KeyPress
e.KeyChar = ChrW(0) '禁止用戶(hù)在其中輸入任何的文字
End Sub
'**************************************************************
'通信端口對(duì)象的DataReceived事件程序
'當(dāng)有數(shù)據(jù)超過(guò)ReceivedBytesThreshold屬性設(shè)定值會(huì)引發(fā)此事件
'接收的程序可以寫(xiě)在此事件程序中
'由于此事件的引發(fā)是在另一個(gè)線程，因此必須使用委派來(lái)處理
'**************************************************************
Private Sub RS232_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles RS232.DataReceived
If e.EventType <> SerialData.Chars Then Exit Sub '判斷接收的數(shù)據(jù)是否為字符
Dim InString As String
InString = RS232.ReadExisting '取得字符串
DisplayText(InString) '顯示數(shù)據(jù)
End Sub
'**************************************************************
'委派子程序
'處理上述通信端口的接收事件
'由于欲將數(shù)據(jù)顯示到接收文字框中，因此必須檢查是否由另外的Thread
'所調(diào)用的，若是，則必須先創(chuàng)建委派對(duì)象
'Invoke用于在擁有控件基礎(chǔ)窗口控制代碼的線程上執(zhí)行委派
'**************************************************************
Private Sub DisplayText(ByVal comData As String)
'如果調(diào)用txtReceive的是另外的線程，返回True
If Me.txtReceive.InvokeRequired Then
'利用委派型別創(chuàng)建委派對(duì)象，并指定委派的函數(shù)
Dim d As New SetTextCallback(AddressOf DisplayText)
'用大括號(hào){} 括住初始值，藉以初始化數(shù)組的值。
Me.Invoke(d, New Object() {comData}) '以指定的自變量清單調(diào)用函數(shù)
Else '相同的線程
txtReceive.Text += comData '將收到的數(shù)據(jù)入接收文字框中
End If
End Sub '更多vb.net源碼和實(shí)例，請(qǐng)關(guān)注lob.cn (樂(lè) 博 網(wǎng))
'**************************************************************
'傳送按鈕的Click事件
'以Write方法送出文字框內(nèi)的數(shù)據(jù)
'**************************************************************
Private Sub btnSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSend.Click
RS232.Write(txtSend.Text & vbCr)
End Sub
End Class
