The Win32_DeviceChangeEvent reports just the type of event that occurred and the Time of the event (uint64, representing 100-nanosecond intervals after January 1, 1601, UTC). No that much useful if you also want to know what arrived or was removed.
I suggest to use instead the WqlEventQuery class, setting its EventClassName to __InstanceOperationEvent.
This system class provides a TargetInstance
property the can be cast to a ManagementBaseObject, the full management object that also provides base information on the Device that generated the event.
Among these information (which include the friendly name of the Device), the PNPDeviceID
, which can be used to build other queries to further inspect the Device referenced.
The WqlEventQuery
's Condition property can be set here to TargetInstance ISA 'Win32_DiskDrive'
.
It can be set to any other Win32_
class of interest.
Setup the event listener (local machine):
(The event handler is called DeviceChangedEvent
)
var query = new WqlEventQuery() {
EventClassName = "__InstanceOperationEvent",
WithinInterval = new TimeSpan(0, 0, 3),
Condition = @"TargetInstance ISA 'Win32_DiskDrive'"
};
var scope = new ManagementScope("root\CIMV2");
using (var moWatcher = new ManagementEventWatcher(scope, query))
{
moWatcher.Options.Timeout = ManagementOptions.InfiniteTimeout;
moWatcher.EventArrived += new EventArrivedEventHandler(DeviceChangedEvent);
moWatcher.Start();
}
The event handler receives, in e.NewEvent.Properties["TargetInstance"]
, the Management Object representing a Win32_DiskDrive class.
See the Docs about the properties directly available here.
The __InstanceOperationEvent
derived classes of interest, reported by the e.NewEvent.ClassPath.ClassName
, can be:
__InstanceCreationEvent: A new Device arrival has been detected.
__InstanceDeletionEvent: A Device removal has been detected.
__InstanceModificationEvent: An existing device has been modified in some way.
Note that the event is raised in a secondary thread, we need to BeginInvoke()
the UI thread to update the UI with the new information.
? You should avoid Invoke()
here, since it's synchronous: it will block the handler until the method completes. Also, in this context, a dead-lock is not exactly a remote possibility.
See here: Get serial number of USB storage device for a class that provides most of the information available about a device (the information is filtered to show USB devices only, but the filter can be removed).
private void DeviceChangedEvent(object sender, EventArrivedEventArgs e)
{
using (var moBase = (ManagementBaseObject)e.NewEvent.Properties["TargetInstance"].Value)
{
string oInterfaceType = moBase?.Properties["InterfaceType"]?.Value.ToString();
string devicePNPId = moBase?.Properties["PNPDeviceID"]?.Value.ToString();
string deviceDescription = moBase?.Properties["Caption"]?.Value.ToString();
string eventMessage = $"{oInterfaceType}: {deviceDescription} ";
switch (e.NewEvent.ClassPath.ClassName)
{
case "__InstanceDeletionEvent":
eventMessage += " removed";
BeginInvoke(new Action(() => UpdateUI(eventMessage)));
break;
case "__InstanceCreationEvent":
eventMessage += "inserted";
BeginInvoke(new Action(() => UpdateUI(eventMessage)));
break;
case "__InstanceModificationEvent":
default:
Console.WriteLine(e.NewEvent.ClassPath.ClassName);
break;
}
}
}
private void UpdateUI(string message)
{
//Update the UI controls with information provided by the event
}