Question

我是VB新手，我试图让程序输出文本而不是十六进制。我在网上找到了一个名为maxiCOM的程序代码。这是链接http://www.innovatic.dk/knowledg/SerialCOM/SerialCOM.htm。源代码可以在页面底部下载。

不幸的是，程序中的编码水平远高于我的理解水平，我真的不知道如何将输出从十六进制更改为文本。如果有人能向我解释如何做到这一点，我将不胜感激。代码片段是

Public Class MaxiTester

Dim SpaceCount As Byte = 0
Dim LookUpTable As String = "0123456789ABCDEF"
Dim RXArray(2047) As Char ' Text buffer. Must be global to be accessible from more threads.
Dim RXCnt As Integer      ' Length of text buffer. Must be global too.

' Make a new System.IO.Ports.SerialPort instance, which is able to fire events.
Dim WithEvents COMPort As New SerialPort

Private Sub Receiver(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs) Handles COMPort.DataReceived
    Dim RXByte As Byte
    Do
        '----- Start of communication protocol handling -----------------------------------------------------------
        ' The code between the two lines does the communication protocol. In this case, it simply emties the
        '   receive buffer and converts it to text, but for all practical applications, you must replace this part
        '     with a code, which can collect one entire telegram by searching for the telegram
        '       delimiter/termination. In case of a simple ASCII protocol, you may just use ReadLine and receive
        '         in a global string instead of a byte array.
        ' Because this routine runs on a thread pool thread, it does not block the UI, so if you have any data
        '   convertion, encryption, expansion, error detection, error correction etc. to do, do it here.
        RXCnt = 0
        Do
            RXByte = COMPort.ReadByte
            RXArray(RXCnt) = LookUpTable(RXByte >> 4) ' Convert each byte to two hexadecimal characters
            RXCnt = RXCnt + 1
            RXArray(RXCnt) = LookUpTable(RXByte And 15)
            RXCnt = RXCnt + 1
            RXArray(RXCnt) = " "
            RXCnt = RXCnt + 1
            SpaceCount = (SpaceCount + 1) And 31      ' Insert spaces and CRLF for better readability
            If SpaceCount = 0 Then                    ' Insert CRLF after 32 numbers
                RXArray(RXCnt) = Chr(13) ' CR
                RXCnt = RXCnt + 1
                RXArray(RXCnt) = Chr(10) ' LF
                RXCnt = RXCnt + 1
            Else
                If (SpaceCount And 3) = 0 Then        ' Insert two extra spaces for each 4 numbers
                    RXArray(RXCnt) = " "
                    RXCnt = RXCnt + 1
                    RXArray(RXCnt) = " "
                    RXCnt = RXCnt + 1
                End If
            End If
        Loop Until (COMPort.BytesToRead = 0)
        '----- End of communication protocol handling -------------------------------------------------------------
        Me.Invoke(New MethodInvoker(AddressOf Display)) ' Start "Display" on the UI thread
    Loop Until (COMPort.BytesToRead = 0)  ' Don't return if more bytes have become available in the meantime
End Sub

' Text display routine, which appends the received string to any text in the Received TextBox.

Private Sub Display()
    Received.AppendText(New String(RXArray, 0, RXCnt))
End Sub

Answer 1

注意内循环中Do之后的第一行：

RXByte = COMPort.ReadByte

这是代码中唯一一个从COM端口读取实际字节值的点。在此之后，代码使用位移将字节转换为两个十六进制值。您应该创建一个string类型的全局变量，并在它丢失之前将读取的字节值附加到此字符串。

在上一行之后立即添加以下行：

YourString &= Convert.ToChar(RXByte).ToString()

其中YourString是您的全局string变量。

请注意，使用StringBuilder代替string可以获得一定的效率，但我会将其作为练习留给您。

Answer 2

System.Text.Encoding.Unicode.GetString(bytes) 'bytes is your byte array'

在Visual Basic中将字节转换为字符串

2 个答案: