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VB。NET串行端口读取十六进制数据并插入文本框

rfid winforms vb.net

-3

Ammar Ashraf · 技术社区 · 7 年前

我想从连接在我的一个com端口上的UHF RFID阅读器读取数据,数据应该是十六进制,并且必须是一个完整的十六进制,应该粘贴在我用VB制作的windows窗体应用程序的文本框中。净额。

请帮助我,我是VB新手。NET编程。我需要一个vb。此任务的net代码:

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

结束类

1 回复 | 直到 7 年前

David Wilson 7 年前

我明白你的问题。。

线路

hexVal = Convert.ToInt32(c, 16) '16 specifies the base

顺便提一下,您的数据是8位二进制的,串行端口读取器将每个8位作为字符类型读取。

你需要的是使用VB内置函数 Hex

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

将为字符串指定“F”

一切都很好。但是,如果需要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,则在开头添加“0”。

那么,你的台词

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

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

并添加此函数以转换字符,必要时添加“0”。。

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

If..End If