Floppy noise in C# WMI - Win32_LogicalDisk Class

Question

I am trying to track USB device insertions and CD/DVD insertions on Windows by using WMI. However when I use Win32_LogicalDisk class to track those events, floppy starts to make noise.

My queries are like below. First one is for USB and second one is for CD.

q = gcnew WqlEventQuery();
q->EventClassName = "__InstanceCreationEvent";
q->WithinInterval = TimeSpan(0, 0, 3);
q->Condition = "TargetInstance ISA 'Win32_LogicalDisk' and TargetInstance.DriveType = 2 and TargetInstance.DeviceID <> 'A:' and TargetInstance.DeviceID <> 'B:'";
w = gcnew ManagementEventWatcher(scope, q);
w->EventArrived += gcnew EventArrivedEventHandler(USBAdded);
w->Start();

---

q = gcnew WqlEventQuery();
q->EventClassName = "__InstanceModificationEvent";
q->WithinInterval = TimeSpan(0, 0, 3);
q->Condition = "TargetInstance ISA 'Win32_LogicalDisk' and TargetInstance.DriveType = 5 and TargetInstance.DeviceID <> 'A:' and TargetInstance.DeviceID <> 'B:'";
w = gcnew ManagementEventWatcher(scope, q);
w->EventArrived += gcnew EventArrivedEventHandler(LogicalInserted);
w->Start();

Actually it does not make noise on all versions. Any idea will be greatly appreciated.

Answer 1

Based on a Microsoft WMI support message here, I'm not certain a WMI query on Win32_LogicalDisk is going to be able to run without firing up the floppies on each polling interval. I'm trying to find an alternate way of solving this issue myself; as I'm working in managed code, I'm considering just running a timer and enumerating the available drives via DriveInfo.GetDrives.

Update: As I was doing this in a Windows service and already had implemented a message handler along the lines described in this CodeProject article (but with proper exception handling and unmanaged memory cleanup), I simply added handlers for the DBT_DEVICEARRIVAL and DBT_DEVICEREMOVECOMPLETE messages. (Due credit to Chris Dickson for pointing that article out to me here.) I used DriveInfo.GetDrives in the handler to determine which devices had been inserted or removed, as I found that cleaner and simpler than getting at the drive letter via Win32. There's no periodic polling involved, no messy WMI, and drive A now stays nice and quiet.

Answer 2

I have created a new approach from WMI.

void MyDLPWMIDeviceListener::AddInsertUSBHandler()
{
        WqlEventQuery ^q;
        ManagementEventWatcher ^w;
        ManagementScope ^scope = gcnew ManagementScope("root\\CIMV2");
        scope->Options->EnablePrivileges = true;
        try
        {
            q = gcnew WqlEventQuery();
            q->EventClassName = "__InstanceCreationEvent";
            q->WithinInterval = TimeSpan(0, 0, 3);
        q->Condition = "TargetInstance ISA 'Win32_USBControllerDevice'";
            w = gcnew ManagementEventWatcher(scope, q);
            w->EventArrived += gcnew EventArrivedEventHandler(USBAdded);
            w->Start();
        }
        catch (Exception ^ex)
        {
            if (w != nullptr)
                w->Stop();
        }
}

After that I have handled the generated event like below:

void MyDLPWMIDeviceListener::USBAdded(Object ^sender, EventArrivedEventArgs ^e)
    {   
        try {

            PropertyData ^pd = e->NewEvent->Properties["TargetInstance"];
            if (pd != nullptr)
            {
                ManagementBaseObject ^mbo = dynamic_cast<ManagementBaseObject ^>(pd->Value);
                if(mbo != nullptr && mbo->Properties["Dependent"] != nullptr
                    && mbo->Properties["Dependent"]->Value != nullptr) {
                    String ^str = (String ^)mbo->Properties["Dependent"]->Value;
                    str = str->Replace("\"","");
                    String ^splitChar = "=";
                    array<String ^> ^strArr = str->Split(splitChar->ToCharArray());

                    WqlObjectQuery ^wqlQuery = gcnew WqlObjectQuery("Select * from Win32_PnPEntity where DeviceID = '"+strArr[1]+"'");
                    ManagementObjectSearcher ^searcher = gcnew ManagementObjectSearcher(wqlQuery);
                    for each (ManagementObject ^usbCont in searcher->Get()) {
                        String ^pnpDeviceID = (String ^)usbCont->Properties["PNPDeviceID"]->Value;
                        splitChar = "\\";
                        array<String ^> ^pnpDeviceIDArr = pnpDeviceID->Split(splitChar->ToCharArray());
                        if(pnpDeviceIDArr->Length == 3) {
                            if(pnpDeviceIDArr[0] == "USB") {
                                WqlObjectQuery ^wqlQueryDisk = gcnew WqlObjectQuery("Select * from Win32_DiskDrive where PNPDeviceID LIKE '%"+pnpDeviceIDArr[2]+"%'");
                                ManagementObjectSearcher ^searcherDisk = gcnew ManagementObjectSearcher(wqlQueryDisk);
                                ManagementObjectCollection ^collectionDisk = searcherDisk->Get();
                                if(collectionDisk->Count == 0)
                                    continue;
                                else if (collectionDisk->Count == 1) {
                                    for each (ManagementObject ^disk in collectionDisk) {

                                    }
                                }
                                else {
                                    return;
                                }
                            } else {
                                return;
                            }
                        } else {
                            return;
                        }
                    }                   
                }
            }       
        } catch (Exception ^ex) {
        } 
    }