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