Question

我想读取连接在我的一个com端口上的UHF RFID阅读器的数据，数据应该是HEX，并且必须是一个完整的HEX，应该粘贴在我制作的Windows窗体应用程序的文本框中在VB.NET中。

请帮助我，我是VB.NET Programming的新手。我需要一个vb.net代码来完成这项任务：

我的代码：

Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
   For Each s In System.IO.Ports.SerialPort.GetPortNames() 
        ComboBox1.Items.Add(s)
    Next s

End Sub


Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    If ComboBox1.SelectedIndex = -1 Then
        MessageBox.Show("Please select a port")
        Exit Sub
    Else
        SerialPort1.BaudRate = 9600
        SerialPort1.DataBits = 8
        SerialPort1.Parity = IO.Ports.Parity.None
        SerialPort1.StopBits = IO.Ports.StopBits.One
        SerialPort1.PortName = ComboBox1.SelectedItem.ToString
        SerialPort1.Open()
    End If
End Sub

Private Shared buffer As String = ""

Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived

    Try
        Dim rcv As String = _SerialPort1.ReadExisting()
        buffer = String.Concat(buffer, rcv)


        Dim hexVal As Integer
        hexVal = Convert.ToInt32(rcv, 16) '16 specifies the base

        txtReceived.Text = hexVal

    Catch ex As Exception
    End Try

End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    SerialPort1.Close()

End Sub

结束班

Answer 1

我看到了你的问题..

行

./configure --prefix=/usr/local/apache-2.4.20 --with-included-apr

正在尝试将字符转换为int32，但该函数假设传入的值已经是十六进制，并且您的答案完全错误。

顺便提一下，您的数据是8位二进制文件，并且您的串行端口读取器将每个8位读取为char类型。

你需要的是使用VB内置函数hexVal = Convert.ToInt32(c, 16) '16 specifies the base，它取一个整数/字节（在这种情况下是每个字符的ascii代码）并返回一个十六进制值作为字符串，所以

Hex

将“F”分配给字符串

一切都很好。但是，如果您需要2位十六进制字符串，则需要检查返回的字符串是否只有一个字符，如果是，请在开头添加“0”。

所以，你的行

Dim x As Integer = 15
Dim s As String = hex(x)

应替换为..

Dim hexVal As Integer
hexVal = Convert.ToInt32(rcv, 16) '16 specifies the base
txtReceived.Text = hexVal

并添加此函数以转换字符，并在必要时添加“0”..

Dim hexVal As string =""
For Each c As Char In rcv
    hexVal = heval & AsciiCharToHexSring(c)
Next
txtReceived.Text = hexVal

如果每次都不需要2位十六进制数，只需删除Private Function AsciiCharToHexSring(s As Char) As String Dim hexdigit As String = Hex(Asc(s)) If hexdigit.Length = 1 Then hexdigit = "0" & hexdigit End If Return hexdigit End Function块

即可

VB.NET串口读取HEX数据并插入文本框中

1 个答案: