vb.net - 动态添加串行端口并在拔出 USB 时从组合框中删除它们

Question

我试图在用户插入 USB 时动态地将串行端口添加到组合框。到目前为止我有下面的代码。我遇到的问题是，当用户拔出 USB 时，我无法删除串行端口。

 Public Sub adding_items()


        Do While x > 0
            Dim Ports As String() = IO.Ports.SerialPort.GetPortNames()
            For Each Port In Ports
                If ComboBox1.Items.Contains(Port) Then


                Else

                    ComboBox1.Items.Add(Port)
                End If


                If ComboBox2.Items.Contains(Port) Then

                Else

                    ComboBox2.Items.Add(Port)
                End If
                If ComboBox3.Items.Contains(Port) Then


                Else
                    ComboBox3.Items.Add(Port)
                End If
            Next Port

            'deleting = New Threading.Thread(AddressOf deleting_items)
            'deleting.Start()

            'Thread.Sleep(5000)


        Loop





    End Sub

请注意，我没有打开或关闭任何串行端口，只是将它们分配给组合框。

Answer 1

我认为最简单的方法是将端口列表保存在每个Do while loop中。并将其与通过调用 IO.Ports.SerialPort.GetPortNames() 获得的新列表进行比较在下面的循环中。一种方法是找到 set difference两个列表之间。 例如:

Public Sub adding_items()
    'List of ports to compare ports in current list as opposet to previous list
    Dim previousPorts As String() = Nothing
    Do While x > 0
        Dim Ports As String() = IO.Ports.SerialPort.GetPortNames()
                For Each Port In Ports
                    If Not ComboBox1.Items.Contains(Port) Then
                        ComboBox1.Items.Add(Port)
                    End If

                    If Not ComboBox2.Items.Contains(Port) Then
                        ComboBox2.Items.Add(Port)
                    End If

                    If Not ComboBox3.Items.Contains(Port) Then
                        ComboBox3.Items.Add(Port)
                    End If
                Next Port
        If previousPorts is Nothing Then
            previousPorts = Ports
        Else
            ' Get the ports from previousPorts that are nor part of Ports
            Dim differenceQuery = previousPorts.Except(Ports)  
            For Each deletedPort in differenceQuery
                ComboBox1.Items.RemovedeletedPort 
                ComboBox2.Items.RemovedeletedPort
                ComboBox3.Items.RemovedeletedPort  
            Next deletedPort 
            'Save the current port list to compare in the next loop.
            previousPorts = Ports
        End If

        'deleting = New Threading.Thread(AddressOf deleting_items)
                'deleting.Start()

                'Thread.Sleep(5000)
    Loop

    End Sub