VB.NET 串口访问之四（绝密级）

Imports System.IO
Imports System.IO.Ports
Imports System.Runtime.Remoting.Messaging   '这个不忘记
Imports System.Text

Delegate Function CommOp(ByVal pval As String,ByVal pDelay As Integer) As String



Module Module1

    Public WithEvents Rs232 As SerialPort
    Sub Main()

        Rs232 = New SerialPort("COM1",9600,Parity.None,8,StopBits.One)
        If Rs232.IsOpen Then Exit Sub
        Rs232.Open()

        Console.WriteLine("*******执行串口操作*********")
        Dim c As CommOp = New CommOp(AddressOf CommOpWrite)
        c.BeginInvoke("ssssssss",50,Nothing,Nothing)


        ' Dim itfAR As IAsyncResult = c.BeginInvoke("ssssssss",New AsyncCallback(AddressOf CommOpComplete),"操作完成")

        '继续其他工作


        Console.ReadLine()
    End Sub

    '
    Sub CommOpComplete(ByVal itfAR As IAsyncResult)
        Console.WriteLine("已经完成数据处理")

        Dim ar As AsyncResult = CType(itfAR,AsyncResult)
        Dim c As CommOp = CType(ar.AsyncDelegate,CommOp)

        Console.WriteLine("输出的结果{0}",c.EndInvoke(itfAR).ToString)

        '接受返回的信息
        Dim Msg As String = CType(itfAR.AsyncState,String)
        Console.WriteLine(Msg)


    End Sub

    Function CommOpWrite(ByVal pVal As String,ByVal pDelay As Integer) As String
        Rs232.Write(pVal)

        Threading.Thread.Sleep(pDelay)

        Dim buf() As Byte
        Dim Builder As StringBuilder = New StringBuilder '避免在事件处理方法中反复的创建，所以定义到外面 

        '输入模块的命令是@01，返回>0F00 +vbcrlf
        Dim TT As Integer
        Dim bTimeOver As Boolean = False

        TT = Environment.TickCount
        bTimeOver = False
        Do
            If Rs232.BytesToRead >= 5 Then Exit Do
            If Environment.TickCount - TT > 1000 Then bTimeOver = True
        Loop Until bTimeOver

        If bTimeOver Then
            Return String.Empty
        Else
            Dim n As Integer = Rs232.BytesToRead
            ReDim buf(n - 1)
            Rs232.Read(buf,n)
            For Each b As Byte In buf
                Builder.Append(b.ToString("X2") + " ")
            Next

            Console.WriteLine(Builder.ToString)
            Return Builder.ToString

        End If
    End Function


End Module

（编辑：李大同）

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