如何從vb.net的串口讀取數據？

Question

我創建了一個類，並且有一個名爲SendUSSD的子類，當它被調用時，它將* 123＃這樣的ussd代碼發送到一個連接了gsm移動設備的COM端口。這ussd應該返回移動餘額。

If IsOpen = True Then 'checks if the port is open 
      SMSPort.WriteLine("AT+CUSD=1,""*123#""" vbCr) 'this sends the ussd code 
      Form1.TextBox2.Text = SMSPort.ReadLine().ToString() 'this shows the response 
End If 

現在問題是有時我得到像「你目前的餘額是如此之多」的完整回覆。但是，大多數情況下，我會收到「你的curr」的部分信息。我的猜測是需要一些時間才能得到響應，那麼如何使這個Form1.TextBox2.Text = SMSPort.ReadLine（）。ToString（）行等到最後一個字符是一個完全停止出現然後執行該行？

Answer 1

即時通訊使用此類來連接通訊端口。

'connect like this 
Public comm As New CommunicationManager 
comm.Parity = "None" 
    comm.StopBits = "One" 
    comm.DataBits = "8" 
    comm.BaudRate = "38400" 
    comm.PortName = comport_ismi 
    comm.OpenPort() 

和類

Imports System.Text 
    Imports System.Drawing 
    Imports System.IO.Ports 
    Imports System.Windows.Forms 

Public Class CommunicationManager 
#Region "Manager Enums" 
    ''' <summary> 
    ''' enumeration to hold our transmission types 
    ''' </summary> 
    Public Enum TransmissionType 
     Text 
     Hex 
    End Enum 

    ''' <summary> 
    ''' enumeration to hold our message types 
    ''' </summary> 
    Public Enum MessageType 
     Incoming 
     Outgoing 
     Normal 
     Warning 
     [Error] 
    End Enum 
#End Region 

#Region "Manager Variables" 
    'property variables 
    Private _baudRate As String = String.Empty 
    Private _parity As String = String.Empty 
    Private _stopBits As String = String.Empty 
    Private _dataBits As String = String.Empty 
    Private _portName As String = String.Empty 
    Private _transType As TransmissionType 
    Private _displayWindow As RichTextBox 
    'global manager variables 
    Private MessageColor As Color() = {Color.Blue, Color.Green, Color.Black, Color.Orange, Color.Red} 
    Private comPort As New SerialPort() 
#End Region 

#Region "Manager Properties" 
    ''' <summary> 
    ''' Property to hold the BaudRate 
    ''' of our manager class 
    ''' </summary> 
    Public Property BaudRate() As String 
     Get 
      Return _baudRate 
     End Get 
     Set(value As String) 
      _baudRate = value 
     End Set 
    End Property 

    ''' <summary> 
    ''' property to hold the Parity 
    ''' of our manager class 
    ''' </summary> 
    Public Property Parity() As String 
     Get 
      Return _parity 
     End Get 
     Set(value As String) 
      _parity = value 
     End Set 
    End Property 

    ''' <summary> 
    ''' property to hold the StopBits 
    ''' of our manager class 
    ''' </summary> 
    Public Property StopBits() As String 
     Get 
      Return _stopBits 
     End Get 
     Set(value As String) 
      _stopBits = value 
     End Set 
    End Property 

    ''' <summary> 
    ''' property to hold the DataBits 
    ''' of our manager class 
    ''' </summary> 
    Public Property DataBits() As String 
     Get 
      Return _dataBits 
     End Get 
     Set(value As String) 
      _dataBits = value 
     End Set 
    End Property 

    ''' <summary> 
    ''' property to hold the PortName 
    ''' of our manager class 
    ''' </summary> 
    Public Property PortName() As String 
     Get 
      Return _portName 
     End Get 
     Set(value As String) 
      _portName = value 
     End Set 
    End Property 

    ''' <summary> 
    ''' property to hold our TransmissionType 
    ''' of our manager class 
    ''' </summary> 
    Public Property CurrentTransmissionType() As TransmissionType 
     Get 
      Return _transType 
     End Get 
     Set(value As TransmissionType) 
      _transType = value 
     End Set 
    End Property 

    ''' <summary> 
    ''' property to hold our display window 
    ''' value 
    ''' </summary> 
    Public Property DisplayWindow() As RichTextBox 
     Get 
      Return _displayWindow 
     End Get 
     Set(value As RichTextBox) 
      _displayWindow = value 
     End Set 
    End Property 
#End Region 

#Region "Manager Constructors" 
    ''' <summary> 
    ''' Constructor to set the properties of our Manager Class 
    ''' </summary> 
    ''' <param name="baud">Desired BaudRate</param> 
    ''' <param name="par">Desired Parity</param> 
    ''' <param name="sBits">Desired StopBits</param> 
    ''' <param name="dBits">Desired DataBits</param> 
    ''' <param name="name">Desired PortName</param> 
    Public Sub New(baud As String, par As String, sBits As String, dBits As String, name As String, rtb As RichTextBox) 
     _baudRate = baud 
     _parity = par 
     _stopBits = sBits 
     _dataBits = dBits 
     _portName = name 
     _displayWindow = rtb 
     'now add an event handler 
     AddHandler comPort.DataReceived, New SerialDataReceivedEventHandler(AddressOf comPort_DataReceived) 
    End Sub 

    ''' <summary> 
    ''' Comstructor to set the properties of our 
    ''' serial port communicator to nothing 
    ''' </summary> 
    Public Sub New() 
     _baudRate = String.Empty 
     _parity = String.Empty 
     _stopBits = String.Empty 
     _dataBits = String.Empty 
     _portName = comport_ismi 
     _displayWindow = Nothing 
     'add event handler 
     AddHandler comPort.DataReceived, New SerialDataReceivedEventHandler(AddressOf comPort_DataReceived) 
    End Sub 
#End Region 

#Region "WriteData" 
    Public Sub WriteData(msg As String) 
     Select Case CurrentTransmissionType 
      Case TransmissionType.Text 
       'first make sure the port is open 
       'if its not open then open it 
       If Not (comPort.IsOpen = True) Then 
        comPort.Open() 
       End If 
       'send the message to the port 
       comPort.Write(msg) 
       'display the message 
       DisplayData(MessageType.Outgoing, msg & Convert.ToString(vbLf)) 
       Exit Select 
      Case TransmissionType.Hex 
       Try 
        'convert the message to byte array 
        Dim newMsg As Byte() = HexToByte(msg) 
        'send the message to the port 
        comPort.Write(newMsg, 0, newMsg.Length) 
        'convert back to hex and display 
        DisplayData(MessageType.Outgoing, ByteToHex(newMsg) & Convert.ToString(vbLf)) 
       Catch ex As FormatException 
        'display error message 
        DisplayData(MessageType.[Error], ex.Message) 
       Finally 
        _displayWindow.SelectAll() 
       End Try 
       Exit Select 
      Case Else 
       'first make sure the port is open 
       'if its not open then open it 
       If Not (comPort.IsOpen = True) Then 
        comPort.Open() 
       End If 
       'send the message to the port 
       comPort.Write(msg) 
       'display the message 
       DisplayData(MessageType.Outgoing, msg & Convert.ToString(vbLf)) 
       Exit Select 
     End Select 
    End Sub 
#End Region 

#Region "HexToByte" 
    ''' <summary> 
    ''' method to convert hex string into a byte array 
    ''' </summary> 
    ''' <param name="msg">string to convert</param> 
    ''' <returns>a byte array</returns> 
    Private Function HexToByte(msg As String) As Byte() 
     'remove any spaces from the string 
     msg = msg.Replace(" ", "") 
     'create a byte array the length of the 
     'divided by 2 (Hex is 2 characters in length) 
     Dim comBuffer As Byte() = New Byte(msg.Length/2 - 1) {} 
     'loop through the length of the provided string 
     For i As Integer = 0 To msg.Length - 1 Step 2 
      'convert each set of 2 characters to a byte 
      'and add to the array 
      comBuffer(i/2) = CByte(Convert.ToByte(msg.Substring(i, 2), 16)) 
     Next 
     'return the array 
     Return comBuffer 
    End Function 
#End Region 

#Region "ByteToHex" 
    ''' <summary> 
    ''' method to convert a byte array into a hex string 
    ''' </summary> 
    ''' <param name="comByte">byte array to convert</param> 
    ''' <returns>a hex string</returns> 
    Private Function ByteToHex(comByte As Byte()) As String 
     'create a new StringBuilder object 
     Dim builder As New StringBuilder(comByte.Length * 3) 
     'loop through each byte in the array 
     For Each data As Byte In comByte 
      'convert the byte to a string and add to the stringbuilder 
      builder.Append(Convert.ToString(data, 16).PadLeft(2, "0"c).PadRight(3, " "c)) 
     Next 
     'return the converted value 
     Return builder.ToString().ToUpper() 
    End Function 
#End Region 

#Region "DisplayData" 
    ''' <summary> 
    ''' method to display the data to & from the port 
    ''' on the screen 
    ''' </summary> 
    ''' <param name="type">MessageType of the message</param> 
    ''' <param name="msg">Message to display</param> 
    <STAThread> _ 
    Private Sub DisplayData(type As MessageType, msg As String) 
     '_displayWindow.Invoke(New EventHandler(Sub() 
     '           _displayWindow.SelectedText = String.Empty 
     '           _displayWindow.SelectionFont = New Font(_displayWindow.SelectionFont, FontStyle.Bold) 
     '           _displayWindow.SelectionColor = MessageColor(CInt(type)) 
     '           _displayWindow.AppendText(msg) 
     '           _displayWindow.ScrollToCaret() 

     '          End Sub)) 
    End Sub 
#End Region 

#Region "OpenPort" 
    Public Function OpenPort() As Boolean 
     Try 
      'first check if the port is already open 
      'if its open then close it 
      If comPort.IsOpen = True Then 
       comPort.Close() 
      End If 

      'set the properties of our SerialPort Object 
      comPort.BaudRate = Integer.Parse(_baudRate) 
      'BaudRate 
      comPort.DataBits = Integer.Parse(_dataBits) 
      'DataBits 
      comPort.StopBits = DirectCast([Enum].Parse(GetType(StopBits), _stopBits), StopBits) 
      'StopBits 
      comPort.Parity = DirectCast([Enum].Parse(GetType(Parity), _parity), Parity) 
      'Parity 
      comPort.PortName = _portName 
      'PortName 
      'now open the port 
      comPort.Open() 
      'display message 
      DisplayData(MessageType.Normal, "Port AÇILDI: " + DateTime.Now + vbLf) 
      'return true 
      Return True 
     Catch ex As Exception 
      DisplayData(MessageType.[Error], ex.Message) 
      Return False 
     End Try 
    End Function 
#End Region 

#Region "ClosePort" 

    Public Function ClosePort() As Boolean 
     Try 
      'first check if the port is already open 
      'if its open then close it 
      If comPort.IsOpen = True Then 
       comPort.Close() 
      End If 
      'display message 
      DisplayData(MessageType.Normal, "Port KAPANDI: " + DateTime.Now + vbLf) 
      'return true if port is closed 
      If comPort.IsOpen = False Then 
       Return True 
      End If 
      DisplayData(MessageType.Normal, "Kapatmada hata oluştu" & vbLf) 
      Return False 
     Catch ex As Exception 
      DisplayData(MessageType.[Error], ex.Message) 
      Return False 
     End Try 
    End Function 

#End Region 

#Region "SetParityValues" 
    Public Sub SetParityValues(obj As Object) 
     For Each str As String In [Enum].GetNames(GetType(Parity)) 
      DirectCast(obj, ComboBox).Items.Add(str) 
     Next 
    End Sub 
#End Region 

#Region "SetStopBitValues" 
    Public Sub SetStopBitValues(obj As Object) 
     For Each str As String In [Enum].GetNames(GetType(StopBits)) 
      DirectCast(obj, ComboBox).Items.Add(str) 
     Next 
    End Sub 
#End Region 

#Region "SetPortNameValues" 
    Public Sub SetPortNameValues(obj As Object) 

     For Each str As String In SerialPort.GetPortNames() 
      DirectCast(obj, ComboBox).Items.Add(str) 
     Next 
    End Sub 
#End Region 

#Region "comPort_DataReceived" 
    ''' <summary> 
    ''' method that will be called when theres data waiting in the buffer 
    ''' </summary> 
    ''' <param name="sender"></param> 
    ''' <param name="e"></param> 
    Private Sub comPort_DataReceived(sender As Object, e As SerialDataReceivedEventArgs) 
     'determine the mode the user selected (binary/string) 
     Select Case CurrentTransmissionType 
      'user chose string 
      Case TransmissionType.Text 
       'read data waiting in the buffer 
       Dim msg As String = comPort.ReadExisting() 
       'display the data to the user 
       DisplayData(MessageType.Incoming, msg) 
       ' + "\n"); ************** 
       Exit Select 
       'user chose binary 
      Case TransmissionType.Hex 
       'retrieve number of bytes in the buffer 
       Dim bytes As Integer = comPort.BytesToRead 
       'create a byte array to hold the awaiting data 
       Dim comBuffer As Byte() = New Byte(bytes - 1) {} 
       'read the data and store it 
       comPort.Read(comBuffer, 0, bytes) 
       'display the data to the user 
       DisplayData(MessageType.Incoming, ByteToHex(comBuffer)) 
       ' + "\n"); 
       Exit Select 
      Case Else 
       'read data waiting in the buffer 
       Dim str As String = comPort.ReadExisting() 
       'display the data to the user 
       DisplayData(MessageType.Incoming, str) 
       ' + "\n"); 
       Exit Select 
     End Select 
    End Sub 
#End Region 
End Class 

Answer 2

我猜你正在使用DataReceived事件檢索，如果是的話，你可以把數據和由lastIndexOf（Enviroment.NewLine）分裂它。 您將有兩部分，第一部分是一些帶有一些行的字符串，第二部分是不包含更多行的字符串。 您可以將第一部分拆分爲新行，甚至創建一個新事件（LineReceived）。對於第二部分（lastIndexOf（Enviroment.NewLine））之後的部分，將數據連接到下一次將要到達的數據的開始部分，即 。

Answer 3

嘗試設置comm.Newline。可能應該是vbCR。