Catch USB plug and unplug event System.InvalidCastException

问题

I'm trying to detect USB device insertion and remove with WinForm desktop C# application:

 public Form1()
    {
        InitializeComponent();
        USB();
    }

then:

private void USB()
{
     WqlEventQuery weqQuery = new WqlEventQuery();
     weqQuery.EventClassName = "__InstanceOperationEvent";
     weqQuery.WithinInterval = new TimeSpan(0, 0, 3);
     weqQuery.Condition = @"TargetInstance ISA 'Win32_DiskDrive'";  
     var m_mewWatcher = new ManagementEventWatcher(weqQuery);
     m_mewWatcher.EventArrived += new EventArrivedEventHandler(m_mewWatcher_EventArrived);
     m_mewWatcher.Start();           
}

and:

static void m_mewWatcher_EventArrived(object sender, EventArrivedEventArgs e)
    {
        bool bUSBEvent = false;
        foreach (PropertyData pdData in e.NewEvent.Properties)
        {
            ManagementBaseObject mbo = (ManagementBaseObject)e.NewEvent.Properties["TargetInstance"].Value;
           // ManagementBaseObject mbo = (ManagementBaseObject)pdData.Value;
            if (mbo != null)
            {
                foreach (PropertyData pdDataSub in mbo.Properties)
                {
                    if (pdDataSub.Name == "InterfaceType" && pdDataSub.Value.ToString() == "USB")
                    {
                        bUSBEvent = true;
                        break;
                    }
                }

                if (bUSBEvent)
                {
                    if (e.NewEvent.ClassPath.ClassName == "__InstanceCreationEvent")
                    {
                        MessageBox.Show ("USB was plugged in");
                    }
                    else if (e.NewEvent.ClassPath.ClassName == "__InstanceDeletionEvent")
                    {
                        MessageBox.Show("USB was plugged out");
                    }
                }
            }
        }
    }

But I got exception with ManagementBaseObject mbo = (ManagementBaseObject)pdData.Value; when detects USB change:

An exception of type 'System.InvalidCastException' occurred in Controller.exe but was not handled in user code

Additional information: Unable to cast object of type 'System.UInt64' to type 'System.Management.ManagementBaseObject'.

edit:

using System;
using System.Windows.Forms;
using System.Management;

namespace test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            WqlEventQuery query = new WqlEventQuery()
            {
                EventClassName = "__InstanceOperationEvent",
                WithinInterval = new TimeSpan(0, 0, 3),
                Condition = @"TargetInstance ISA 'Win32_DiskDrive'"
            };

            using (ManagementEventWatcher MOWatcher = new ManagementEventWatcher(query))
            {
                MOWatcher.EventArrived += new EventArrivedEventHandler(DeviceInsertedEvent);
                MOWatcher.Start();
            }
        }

        private void DeviceInsertedEvent(object sender, EventArrivedEventArgs e)
        {
            using (ManagementBaseObject MOBbase = (ManagementBaseObject)e.NewEvent.Properties["TargetInstance"].Value)
            {
                bool DriveArrival = false;
                string EventMessage = string.Empty;
                string oInterfaceType = MOBbase.Properties["InterfaceType"]?.Value.ToString();

                if (e.NewEvent.ClassPath.ClassName.Equals("__InstanceDeletionEvent"))
                {
                    DriveArrival = false;
                    EventMessage = oInterfaceType + " Drive removed";
                }
                else
                {
                    DriveArrival = true;
                    EventMessage = oInterfaceType + " Drive inserted";
                }
                EventMessage += ": " + MOBbase.Properties["Caption"]?.Value.ToString();
                this.BeginInvoke((MethodInvoker)delegate { this.UpdateUI(DriveArrival, EventMessage); });
            }
        }

        private void UpdateUI(bool IsDriveInserted, string message)
        {
            if (IsDriveInserted)
            {
                this.label1.Text = message;
            }             
            else
            {
                this.label1.Text = message;
            }                
        }
    }
}

回答1:

Here, the ManagementEventWatcher is initialized on a Button.Click() event. Of course, you can initialize it elsewhere. In Form.Load() for example.

The ManagementEventWatcher.EventArrived event is subscribed, setting the delegate to private void DeviceInsertedEvent(). The watching procedure is the started using ManagementEventWatcher.Start() (MOWatcher.Start();)

When an event is notified, the EventArrivedEventArgs e.NewEvent.Properties["TargetInstance"].Value will be set to a ManagementBaseObject, which will reference a Win32_DiskDrive WMI/CIM class.
Read the documentation to see what informations are available in this class.

This event is not rasised in the UI Thread. To notify the main UI interface of the nature of the event, we need to .Invoke() a method in that thread.

this.BeginInvoke((MethodInvoker)delegate { this.UpdateUI(DriveArrival, EventMessage); });

Here, the private void UpdateUI() method is called, delegating the UI update to a method which is executed in the UI thread.

Update:
Added RegisterWindowMessage() to register QueryCancelAutoPlay, to prevent the AutoPlay window from popping up in front of our Form, stealing the focus.

A visual sample of the results:

[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
internal static extern uint RegisterWindowMessage(string lpString);

private uint CancelAutoPlay = 0;

private void button1_Click(object sender, EventArgs e)
{
    WqlEventQuery query = new WqlEventQuery() {
        EventClassName = "__InstanceOperationEvent",
        WithinInterval = new TimeSpan(0, 0, 3),
        Condition = @"TargetInstance ISA 'Win32_DiskDrive'"
    };

    ManagementScope scope = new ManagementScope("root\\CIMV2");
    using (ManagementEventWatcher MOWatcher = new ManagementEventWatcher(query))
    {
        MOWatcher.Options.Timeout = ManagementOptions.InfiniteTimeout;
        MOWatcher.EventArrived += new EventArrivedEventHandler(DeviceChangedEvent);
        MOWatcher.Start();
    }
}

private void DeviceChangedEvent(object sender, EventArrivedEventArgs e)
{
    using (ManagementBaseObject MOBbase = (ManagementBaseObject)e.NewEvent.Properties["TargetInstance"].Value)
    {
        bool DriveArrival = false;
        string EventMessage = string.Empty;
        string oInterfaceType = MOBbase.Properties["InterfaceType"]?.Value.ToString();

        if (e.NewEvent.ClassPath.ClassName.Equals("__InstanceDeletionEvent"))
        {
            DriveArrival = false;
            EventMessage = oInterfaceType + " Drive removed";
        }
        else
        {
            DriveArrival = true;
            EventMessage = oInterfaceType + " Drive inserted";
        }
        EventMessage += ": " + MOBbase.Properties["Caption"]?.Value.ToString();
        this.BeginInvoke((MethodInvoker)delegate { this.UpdateUI(DriveArrival, EventMessage); });
    }
}


private void UpdateUI(bool IsDriveInserted, string message)
{
    if (IsDriveInserted)
        this.lblDeviceArrived.Text = message;
    else
        this.lblDeviceRemoved.Text = message;
}


[SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
protected override void WndProc(ref Message m)
{
    base.WndProc(ref m);

    if (CancelAutoPlay == 0)
        CancelAutoPlay = RegisterWindowMessage("QueryCancelAutoPlay");

    if ((int)m.Msg == CancelAutoPlay) { m.Result = (IntPtr)1; }
}

来源：https://stackoverflow.com/questions/52598371/catch-usb-plug-and-unplug-event-system-invalidcastexception