下面显示了如何在 VS 2022 中为 .NET 6 和 .NET Framework 4.8 获取 VB.NET 中的 COM 设备列表。如果添加/删除 USB COM（串行端口）设备，将更新 ComboBox。
Windows 窗体应用程序: (.NET 6)
创建一个新项目：Windows Forms App（名称：SerialPortGetComDevices）
下载/安装以下 NuGet 包:
System.IO.Ports-
System.Management
Windows 窗体应用程序（.NET 框架）- v4.8：
创建一个新项目：Windows Forms App (.NET Framework)（名称：SerialPortGetComDevices）
添加参考:
- 在 VS 菜单中，单击项目
- 选择添加参考...
- 选择组件
- 检查系统管理
- 点击好的
以下说明对于Windows Forms App 和Windows Forms App (.NET Framework) 都是相同的。
创建班级（名称：ComPortInfo.vb）
Public Class ComPortInfo
Public Property Caption As String
Public Property PortName As String
End Class
打开解决方案资源管理器:
- 在 VS 菜单中，单击看法
- 选择解决方案资源管理器
打开属性窗口:
添加Load事件处理器
- 在解决方案资源管理器中，右键单击
Form1.vb 并选择 View Designer。
- 在属性窗口中，单击
- 双击加载
添加FormClosing事件处理器
- 在解决方案资源管理器中，右键单击
Form1.vb 并选择 View Designer。
- 在属性窗口中，单击
- 双击关闭表格
向窗体添加组合框（名称：ComboBoxComPorts）
- 在 VS 菜单中，单击看法
- 选择工具箱
- 在工具箱中，选择组合框, 并将其拖到窗体中。
- 在“属性”窗口中，将
(Name) 更改为ComboBoxComPorts
- 在“属性”窗口中，将
DropDownStyle 更改为DropDownList
选择以下选项之一。第一个选项使用 ManagementEventWatcher 来检测 USB 设备的插入和移除。第二个选项覆盖WndProc。
笔记: WndProc版本（选项2）的性能似乎稍好一些。
选项1（管理事件观察者）
笔记: 检测USB设备插拔的代码，改编自here。
Form1.vb
Imports System.ComponentModel
Imports System.Management
Imports System.IO.Ports
Public Class Form1
'create new instance
Private _comPorts As BindingList(Of ComPortInfo) = New BindingList(Of ComPortInfo)
Private _managementEventWatcher1 As ManagementEventWatcher = New ManagementEventWatcher()
Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
InitializeManagementEventWatcher()
UpdateCOM()
'set properties
ComboBoxComPorts.DataSource = _comPorts
ComboBoxComPorts.DisplayMember = "Caption"
ComboBoxComPorts.ValueMember = "PortName"
End Sub
Private Sub GetComPorts()
'this method Is only called from 'UpdateCOM'
'_comPorts' is only modified in this method
Dim portDict As Dictionary(Of String, String) = New Dictionary(Of String, String)
'clear existing data
_comPorts.Clear()
'get port names
For Each pName As String In SerialPort.GetPortNames()
If Not portDict.ContainsKey(pName) Then
portDict.Add(pName, pName) 'add to Dictionary
End If
Next
'get USB COM ports - this may result in a more descriptive name than 'COM1'
Using searcherPnPEntity As ManagementObjectSearcher = New ManagementObjectSearcher("SELECT Name FROM Win32_PnPEntity WHERE PNPClass = 'Ports'")
For Each objPnPEntity As ManagementObject In searcherPnPEntity.Get()
If objPnPEntity Is Nothing Then
Continue For
End If
'get name
Dim name As String = objPnPEntity("Name")?.ToString()
If Not String.IsNullOrEmpty(name) AndAlso name.ToUpper().Contains("COM") Then
Dim portName As String = name.Substring(name.IndexOf("(") + 1, name.IndexOf(")") - name.IndexOf("(") - 1)
If Not portDict.ContainsKey(portName) Then
portDict.Add(portName, name) 'add to Dictionary
Else
portDict(portName) = name 'update value
End If
End If
Next
End Using
'add items from Dictionary to BindingList
For Each kvp As KeyValuePair(Of String, String) In portDict
_comPorts.Add(New ComPortInfo() With {.Caption = kvp.Value, .PortName = kvp.Key}) 'add
Next
End Sub
Private Sub InitializeManagementEventWatcher()
'see https:'learn.microsoft.com/en-us/windows/win32/wmisdk/within-clause
'WITHIN sets the polling interval in seconds
'polling too frequently may reduce performance
Dim query As WqlEventQuery = New WqlEventQuery("SELECT * FROM __InstanceOperationEvent WITHIN 2 WHERE TargetInstance ISA 'Win32_PnPEntity'")
'Dim query As WqlEventQuery = New WqlEventQuery("SELECT * FROM __InstanceOperationEvent WITHIN 1 WHERE TargetInstance ISA 'Win32_PnPEntity'")
'set property
_managementEventWatcher1.Query = query
'subscribe to event
AddHandler _managementEventWatcher1.EventArrived, AddressOf ManagementEventWatcher_EventArrived
'start
_managementEventWatcher1.Start()
End Sub
Private Sub LogMsg(msg As String, Optional includeTimestamp As Boolean = True)
If includeTimestamp Then
msg = $"{DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss.fff")} - {msg}"
End If
Debug.WriteLine(msg)
End Sub
Public Sub UpdateCOM()
If ComboBoxComPorts.InvokeRequired Then
'LogMsg("ComboBoxComPorts.InvokeRequired")
ComboBoxComPorts.Invoke(New MethodInvoker(Sub()
GetComPorts()
End Sub))
Else
GetComPorts()
End If
End Sub
Public Sub ManagementEventWatcher_EventArrived(sender As Object, e As EventArrivedEventArgs)
Dim obj As ManagementBaseObject = DirectCast(e.NewEvent, ManagementBaseObject)
Dim target As ManagementBaseObject = If(obj("TargetInstance") IsNot Nothing, DirectCast(obj("TargetInstance"), ManagementBaseObject), Nothing)
Dim usbEventType As String = String.Empty
Select Case target.ClassPath.ClassName
Case "__InstanceCreationEvent"
usbEventType = "added"
Case "__InstanceDeletionEvent"
usbEventType = "removed"
Case Else
usbEventType = target.ClassPath.ClassName
End Select
If target("PNPClass") IsNot Nothing AndAlso target("PNPClass").ToString() = "Ports" Then
'update COM ports
UpdateCOM()
End If
End Sub
Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
'stop
_managementEventWatcher1.Stop()
'unsubscribe from event
RemoveHandler _managementEventWatcher1.EventArrived, AddressOf ManagementEventWatcher_EventArrived
End Sub
End Class
选项 2（覆盖 WndProc）
笔记: 检测USB设备插拔的代码，改编自here。
添加模块（名称：UsbDeviceNotification.vb）
Imports System.Runtime.InteropServices
Module UsbDeviceNotification
Public Const DbtDeviceArrival As Integer = &H8000 'device added
Public Const DbtDeviceRemoveComplete As Integer = &H8004 'device removed
Public Const WM_DEVICECHANGE As Integer = &H219 'device change event
Public Const DBT_DEVTYP_DEVICEINTERFACE As Integer = 5
Private ReadOnly _guidDevInterfaceUSBDevice As Guid = New Guid("A5DCBF10-6530-11D2-901F-00C04FB951ED") 'USB devices
Private _notificationHandle As IntPtr
Declare Auto Function RegisterDeviceNotification Lib "user32" (recipient As IntPtr, notificationFilter As IntPtr, flags As Integer) As IntPtr
Declare Auto Function UnregisterDeviceNotification Lib "user32" (hwnd As IntPtr) As Boolean
<StructLayout(LayoutKind.Sequential)>
Private Structure DEV_BROADCAST_DEVICEINTERFACE
Dim Size As Integer
Dim DeviceType As Integer
Dim Reserved As Integer
Dim ClassGuid As Guid
Dim Name As Short
End Structure
Public Sub RegisterUsbDeviceNotification(hwnd As IntPtr)
'Registers a window to receive notifications when USB devices are plugged or unplugged.
Dim dbi As DEV_BROADCAST_DEVICEINTERFACE = New DEV_BROADCAST_DEVICEINTERFACE() With
{
.DeviceType = DBT_DEVTYP_DEVICEINTERFACE,
.ClassGuid = _guidDevInterfaceUSBDevice
}
dbi.Size = Marshal.SizeOf(dbi)
Dim buffer As IntPtr = Marshal.AllocHGlobal(dbi.Size)
Marshal.StructureToPtr(dbi, buffer, True)
_notificationHandle = RegisterDeviceNotification(hwnd, buffer, 0)
End Sub
Public Sub UnregisterUsbDeviceNotification()
UnregisterDeviceNotification(_notificationHandle)
End Sub
End Module
Form1.vb
Imports System.ComponentModel
Imports System.Management
Imports System.IO.Ports
Imports System.Threading
Public Class Form1
'create new instance
Private _comPorts As BindingList(Of ComPortInfo) = New BindingList(Of ComPortInfo)
Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
UpdateCOM()
'set properties
ComboBoxComPorts.DataSource = _comPorts
ComboBoxComPorts.DisplayMember = "Caption"
ComboBoxComPorts.ValueMember = "PortName"
End Sub
Private Sub GetComPorts()
'this method Is only called from 'UpdateCOM'
'_comPorts' is only modified in this method
Dim portDict As Dictionary(Of String, String) = New Dictionary(Of String, String)
'clear existing data
_comPorts.Clear()
'get port names
For Each pName As String In SerialPort.GetPortNames()
If Not portDict.ContainsKey(pName) Then
portDict.Add(pName, pName) 'add to Dictionary
End If
Next
'get USB COM ports - this may result in a more descriptive name than 'COM1'
Using searcherPnPEntity As ManagementObjectSearcher = New ManagementObjectSearcher("SELECT Name FROM Win32_PnPEntity WHERE PNPClass = 'Ports'")
If searcherPnPEntity IsNot Nothing Then
For Each objPnPEntity As ManagementBaseObject In searcherPnPEntity.Get()
If objPnPEntity Is Nothing Then
Continue For
End If
'get name
Dim name As String = objPnPEntity("Name")?.ToString()
If Not String.IsNullOrEmpty(name) AndAlso name.ToUpper().Contains("COM") Then
Dim portName As String = name.Substring(name.IndexOf("(") + 1, name.IndexOf(")") - name.IndexOf("(") - 1)
If Not portDict.ContainsKey(portName) Then
portDict.Add(portName, name) 'add to Dictionary
Else
portDict(portName) = name 'update value
End If
End If
Next
End If
End Using
'add items from Dictionary to BindingList
For Each kvp As KeyValuePair(Of String, String) In portDict
_comPorts.Add(New ComPortInfo() With {.Caption = kvp.Value, .PortName = kvp.Key}) 'add
Next
End Sub
Private Sub LogMsg(msg As String, Optional includeTimestamp As Boolean = True)
If includeTimestamp Then
msg = $"{DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss.fff")} - {msg}"
End If
Debug.WriteLine(msg)
End Sub
Public Sub UpdateCOM()
'since this method/Sub is called from WndProc,
'it needs to run on a new thread
Dim threadProc As System.Threading.Thread = New System.Threading.Thread(Sub()
If ComboBoxComPorts.InvokeRequired Then
'LogMsg("ComboBoxComPorts.InvokeRequired")
ComboBoxComPorts.Invoke(New MethodInvoker(Sub()
GetComPorts()
End Sub))
Else
GetComPorts()
End If
End Sub)
threadProc.SetApartmentState(System.Threading.ApartmentState.STA)
threadProc.Start()
End Sub
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
If m.Msg = UsbDeviceNotification.WM_DEVICECHANGE Then
Select Case CInt(m.WParam)
Case UsbDeviceNotification.DbtDeviceRemoveComplete
UpdateCOM()
Case UsbDeviceNotification.DbtDeviceArrival
UpdateCOM()
End Select
End If
MyBase.WndProc(m)
End Sub
Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
End Sub
End Class
以下 PowerShell 命令也可能提供有用的信息。
电源外壳:
Get-CimInstance -Namespace RootCimv2 -Query "Select * From Win32_SerialPort Where Name like '%COM%'"Get-CimInstance -Namespace RootCimv2 -Query "Select * From Win32_SerialPortConfiguration"Get-CimInstance -Namespace RootCimv2 -Query "Select * From Win32_PnPEntity where PnPClass = 'Ports' and Name like '%COM%'"-
mode
资源: