Question

我正在设计一个windows userform，通过串口与微控制器进行交互。

GUI包含多个用户表单，这些用户表单将使用相同的串行端口。我研究了如何做到这一点，我发现了不同的想法。有些我不知道它是否适用于其他我不知道如何在代码中实现它。假设我有

Form1：Start.vb Form2：Shield1.vb

1）我可以将start userform中的串口声明为：

Public Shared SerialPort1 As New System.IO.Ports.SerialPort

并以其他形式使用它？

2）第一种选择：使用模块声明新的Serialport

Module Module1
Public WithEvents mySerialPort1 As New IO.Ports.SerialPort

Private Sub mySerialPort1_DataReceived(sender As Object, _
                                       e As System.IO.Ports.SerialDataReceivedEventArgs) _
                                   Handles mySerialPort1.DataReceived
End Sub
End Module

这种方法对吗？如果是，我如何在表格代码中使用它？如何在表单代码中包含DataReceived事件？

3）第二种选择：在开始表单中使用Serialport的构造函数，然后将数据传递给本文中提到的其他表单：

private void OnSetup(object sender, EventArgs e)
{
this.port = new SerialPort(...);
// TODO: initialize port

Form2 f2 = new Form2(this.port);
f2.Show();
Form3 f3 = new Form3(this.port);
f3.Show();
Form4 f4 = new Form4(this.port);
f4.Show();

}

那么活动还包括在内吗？我该如何使用它们？

4）第三种选择：使用类似于此解决方案中完成的静态类： Alternate Solution 1

用C＃写的代码在这里吗？我正在VB.net中编写我的程序，但我可以将其作为参考。

对于初学者，推荐哪种解决方案？如果您有其他建议或更正，可以用小码编写吗？

我提前为任何歧义或错误使用的条款道歉。

谢谢！

Answer 1

我会遵循“Singleton”设计模式，这样可以确保只创建一个类的一个实例。这是一个广为接受的类这样的模板：

Public NotInheritable Class MySerial
Private Shared ReadOnly _instance As New Lazy(Of MySerial)(Function() New
    MySerial(), System.Threading.LazyThreadSafetyMode.ExecutionAndPublication)

Private Sub New()
End Sub

Public Shared ReadOnly Property Instance() As MySerial
    Get
        Return _instance.Value
    End Get
End Property

结束班

在New()方法中，您应该根据需要设置串口。然后，无论您在何处使用该端口，都可以引用实例：

Dim singletonSerial As MySerial = MySerial.Instance

这是规范模式，用于确保您只有一个对象副本而无需使用静态类。这是一种可以追溯到20多年的设计模式，当您只需要一个对象的副本时，它仍然可以很好地工作。

Answer 2

我发现这是一个非常有用的串口C＃类的示例： C# Singleton Example

作为一名初学者，我使用了Code转换器在VB.Net中使用它。如果结果代码正确并且我可以使用它，你能告诉我吗？非常感谢！！

Imports System
Imports System.IO
Imports System.IO.Ports
Imports System.Threading

Namespace HeiswayiNrird.Singleton

Public NotInheritable Class SerialPortManager

    Private Shared lazy As Lazy(Of SerialPortManager) = New Lazy(Of SerialPortManager)(() => {  }, New SerialPortManager)

    Public Shared ReadOnly Property Instance As SerialPortManager
        Get
            Return lazy.Value
        End Get
    End Property

    Private _serialPort As SerialPort

    Private _readThread As Thread

    Private _keepReading As Boolean

    Private Sub New()
        MyBase.New
        Me._serialPort = New SerialPort
        Me._readThread = Nothing
        Me._keepReading = false
    End Sub

    ''' <summary>
    ''' Update the serial port status to the event subscriber
    ''' </summary>
    Public Event OnStatusChanged As EventHandler(Of String)

    ''' <summary>
    ''' Update received data from the serial port to the event subscriber
    ''' </summary>
    Public Event OnDataReceived As EventHandler(Of String)

    ''' <summary>
    ''' Update TRUE/FALSE for the serial port connection to the event subscriber
    ''' </summary>
    Public Event OnSerialPortOpened As EventHandler(Of Boolean)

    ''' <summary>
    ''' Return TRUE if the serial port is currently connected
    ''' </summary>
    Public ReadOnly Property IsOpen As Boolean
        Get
            Return Me._serialPort.IsOpen
        End Get
    End Property

    ''' <summary>
    ''' Open the serial port connection using basic serial port settings
    ''' </summary>
    ''' <param name="portname">COM1 / COM3 / COM4 / etc.</param>
    ''' <param name="baudrate">0 / 100 / 300 / 600 / 1200 / 2400 / 4800 / 9600 / 14400 / 19200 / 38400 / 56000 / 57600 / 115200 / 128000 / 256000</param>
    ''' <param name="parity">None / Odd / Even / Mark / Space</param>
    ''' <param name="databits">5 / 6 / 7 / 8</param>
    ''' <param name="stopbits">None / One / Two / OnePointFive</param>
    ''' <param name="handshake">None / XOnXOff / RequestToSend / RequestToSendXOnXOff</param>
    Public Sub Open(Optional ByVal portname As String = "COM1", Optional ByVal baudrate As Integer = 9600, Optional ByVal parity As Parity = Parity.None, Optional ByVal databits As Integer = 8, Optional ByVal stopbits As StopBits = StopBits.One, Optional ByVal handshake As Handshake = Handshake.None)
        Me.Close

        Try 
            Me._serialPort.PortName = portname
            Me._serialPort.BaudRate = baudrate
            Me._serialPort.Parity = parity
            Me._serialPort.DataBits = databits
            Me._serialPort.StopBits = stopbits
            Me._serialPort.Handshake = handshake
            Me._serialPort.ReadTimeout = 50
            Me._serialPort.WriteTimeout = 50
            Me._serialPort.Open
            Me.StartReading

        Catch  As IOException
            If (Not (OnStatusChanged) Is Nothing) Then
                OnStatusChanged(Me, String.Format("{0} does not exist.", portname))
            End If

        Catch  As UnauthorizedAccessException
            If (Not (OnStatusChanged) Is Nothing) Then
                OnStatusChanged(Me, String.Format("{0} already in use.", portname))
            End If

        Catch ex As Exception
            If (Not (OnStatusChanged) Is Nothing) Then
                OnStatusChanged(Me, ("Error: " + ex.Message))
            End If

        End Try

        If Me._serialPort.IsOpen Then
            Dim sb As String = StopBits.None.ToString.Substring(0, 1)
            Select Case (Me._serialPort.StopBits)
                Case StopBits.One
                    sb = "1"
                Case StopBits.OnePointFive
                    sb = "1.5"
                Case StopBits.Two
                    sb = "2"
            End Select

            Dim p As String = Me._serialPort.Parity.ToString.Substring(0, 1)
            Dim hs As String = "No Handshake"
            'TODO: Warning!!!, inline IF is not supported ?
            (Me._serialPort.Handshake = Handshake.None)
            Me._serialPort.Handshake.ToString
            If (Not (OnStatusChanged) Is Nothing) Then
                OnStatusChanged(Me, String.Format("Connected to {0}: {1} bps, {2}{3}{4}, {5}.", Me._serialPort.PortName, Me._serialPort.BaudRate, Me._serialPort.DataBits, p, sb, hs))
            End If

            If (Not (OnSerialPortOpened) Is Nothing) Then
                OnSerialPortOpened(Me, true)
            End If

        Else
            If (Not (OnStatusChanged) Is Nothing) Then
                OnStatusChanged(Me, String.Format("{0} already in use.", portname))
            End If

            If (Not (OnSerialPortOpened) Is Nothing) Then
                OnSerialPortOpened(Me, false)
            End If

        End If

    End Sub

    ''' <summary>
    ''' Close the serial port connection
    ''' </summary>
    Public Sub Close()
        Me.StopReading
        Me._serialPort.Close
        If (Not (OnStatusChanged) Is Nothing) Then
            OnStatusChanged(Me, "Connection closed.")
        End If

        If (Not (OnSerialPortOpened) Is Nothing) Then
            OnSerialPortOpened(Me, false)
        End If

    End Sub

    ''' <summary>
    ''' Send/write string to the serial port
    ''' </summary>
    ''' <param name="message"></param>
    Public Sub SendString(ByVal message As String)
        If Me._serialPort.IsOpen Then
            Try 
                Me._serialPort.Write(message)
                If (Not (OnStatusChanged) Is Nothing) Then
                    OnStatusChanged(Me, String.Format("Message sent: {0}", message))
                End If

            Catch ex As Exception
                If (Not (OnStatusChanged) Is Nothing) Then
                    OnStatusChanged(Me, String.Format("Failed to send string: {0}", ex.Message))
                End If

            End Try

        End If

    End Sub

    Private Sub StartReading()
        If Not Me._keepReading Then
            Me._keepReading = true
            Me._readThread = New Thread(ReadPort)
            Me._readThread.Start
        End If

    End Sub

    Private Sub StopReading()
        If Me._keepReading Then
            Me._keepReading = false
            Me._readThread.Join
            Me._readThread = Nothing
        End If

    End Sub

    Private Sub ReadPort()

        While Me._keepReading
            If Me._serialPort.IsOpen Then
                'byte[] readBuffer = new byte[_serialPort.ReadBufferSize + 1];
                Try 
                    'int count = _serialPort.Read(readBuffer, 0, _serialPort.ReadBufferSize);
                    'string data = Encoding.ASCII.GetString(readBuffer, 0, count);
                    Dim data As String = Me._serialPort.ReadLine
                    If (Not (OnDataReceived) Is Nothing) Then
                        OnDataReceived(Me, data)
                    End If

                Catch  As TimeoutException

                End Try

            Else
                Dim waitTime As TimeSpan = New TimeSpan(0, 0, 0, 0, 50)
                Thread.Sleep(waitTime)
            End If


        End While

    End Sub
End Class
End Namespace

以多种形式使用串行端口的方法

2 个答案: