我最终使用 WMI 和 @Hans 的建议来检查哪些串行端口是新的/缺少的。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Diagnostics.Contracts;
using System.IO.Ports;
using System.Management;
public static class SerialPortService
{
private static SerialPort _serialPort;
private static string[] _serialPorts;
private static ManagementEventWatcher arrival;
private static ManagementEventWatcher removal;
static SerialPortService()
{
_serialPorts = GetAvailableSerialPorts();
MonitorDeviceChanges();
}
/// <summary>
/// If this method isn't called, an InvalidComObjectException will be thrown (like below):
/// System.Runtime.InteropServices.InvalidComObjectException was unhandled
///Message=COM object that has been separated from its underlying RCW cannot be used.
///Source=mscorlib
///StackTrace:
/// at System.StubHelpers.StubHelpers.StubRegisterRCW(Object pThis, IntPtr pThread)
/// at System.Management.IWbemServices.CancelAsyncCall_(IWbemObjectSink pSink)
/// at System.Management.SinkForEventQuery.Cancel()
/// at System.Management.ManagementEventWatcher.Stop()
/// at System.Management.ManagementEventWatcher.Finalize()
///InnerException:
/// </summary>
public static void CleanUp()
{
arrival.Stop();
removal.Stop();
}
public static event EventHandler<PortsChangedArgs> PortsChanged;
private static void MonitorDeviceChanges()
{
try
{
var deviceArrivalQuery = new WqlEventQuery("SELECT * FROM Win32_DeviceChangeEvent WHERE EventType = 2");
var deviceRemovalQuery = new WqlEventQuery("SELECT * FROM Win32_DeviceChangeEvent WHERE EventType = 3");
arrival = new ManagementEventWatcher(deviceArrivalQuery);
removal = new ManagementEventWatcher(deviceRemovalQuery);
arrival.EventArrived += (o, args) => RaisePortsChangedIfNecessary(EventType.Insertion);
removal.EventArrived += (sender, eventArgs) => RaisePortsChangedIfNecessary(EventType.Removal);
// Start listening for events
arrival.Start();
removal.Start();
}
catch (ManagementException err)
{
}
}
private static void RaisePortsChangedIfNecessary(EventType eventType)
{
lock (_serialPorts)
{
var availableSerialPorts = GetAvailableSerialPorts();
if (!_serialPorts.SequenceEqual(availableSerialPorts))
{
_serialPorts = availableSerialPorts;
PortsChanged.Raise(null, new PortsChangedArgs(eventType, _serialPorts));
}
}
}
public static string[] GetAvailableSerialPorts()
{
return SerialPort.GetPortNames();
}
}
public enum EventType
{
Insertion,
Removal,
}
public class PortsChangedArgs : EventArgs
{
private readonly EventType _eventType;
private readonly string[] _serialPorts;
public PortsChangedArgs(EventType eventType, string[] serialPorts)
{
_eventType = eventType;
_serialPorts = serialPorts;
}
public string[] SerialPorts
{
get
{
return _serialPorts;
}
}
public EventType EventType
{
get
{
return _eventType;
}
}
}
MonitorDeviceChanges 方法实际上可以查看所有设备更改（如设备管理器），但检查串行端口允许我们仅在更改时引发事件。
要使用代码，只需订阅PortsChanged 事件，例如SerialPortService.PortsChanged += (sender1, changedArgs) => DoSomethingSerial(changedArgs.SerialPorts);
哦，.Raise 方法只是我在某处找到的扩展方法：
/// <summary>
/// Tell subscribers, if any, that this event has been raised.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="handler">The generic event handler</param>
/// <param name="sender">this or null, usually</param>
/// <param name="args">Whatever you want sent</param>
public static void Raise<T>(this EventHandler<T> handler, object sender, T args) where T : EventArgs
{
// Copy to temp var to be thread-safe (taken from C# 3.0 Cookbook - don't know if it's true)
EventHandler<T> copy = handler;
if (copy != null)
{
copy(sender, args);
}
}