vb.net 在 Visual Basic 中将字节转换为字符串
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Converting Byte to String in Visual Basic
提问by a r
I am new to VB and I am trying to get a program to output text instead of hex. I found the code online, a program called maxiCOM. Here is the link http://www.innovatic.dk/knowledg/SerialCOM/SerialCOM.htm. The source code can be downloaded at the bottom of the page.
Unfortunately, the level of coding in the program is far above my level of understanding, and I don't really get how to change the output from hex to text. I would greatly appreciate it if someone could explain to me how to do this. The snippet of the code is
我是 VB 新手，我正在尝试让程序输出文本而不是十六进制。我在网上找到了代码，一个叫maxiCOM的程序。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远超出了我的理解水平，我真的不明白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
回答by dotNET
Notice the first line after Doin your inner loop:
注意Do内部循环中的第一行：
RXByte = COMPort.ReadByte
This is the only point in your code where you have the actual byte value read from the COM port. After this point the code converts the byte into two hex values using bit-shifting. You should create a global variable of stringtype and append the read byte value to this string before it is lost.
这是代码中唯一可以从 COM 端口读取实际字节值的点。在此之后，代码使用位移位将字节转换为两个十六进制值。您应该创建一个全局变量string类型并将读取的字节值附加到该字符串丢失之前。
Add the following line immediately after the above line:
在上述行之后立即添加以下行：
YourString &= Convert.ToChar(RXByte).ToString()
where YourStringis your global stringvariable.
YourString你的全局string变量在哪里。
Note that you can attain some efficiency by using StringBuilderinstead of string, but I'm leaving that for you as exercise.
请注意，您可以通过使用StringBuilder代替 来提高效率string，但我将其留给您作为练习。
回答by John Michael Villegas
System.Text.Encoding.Unicode.GetString(bytes) 'bytes is your byte array'
