Detecting USB device using .NET connectivity

[Crowbar]

Hello. I want to recieve an event notification when the USB device is plug in or unplugged from the system. There is a special System.Management assembly which allows to catch system messages (also notifications from USB controller). I've tried to rebuilt some easy C# examples on LV using .NET event callback chain, it seems I'm missing something (See attached VI's). 

On code example:

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

namespace WMISample
{
  public class WMIReceiveEvent
  {
  public static void Main()
  {
  try
  {
  WqlEventQuery query = new WqlEventQuery(
  "SELECT * FROM __InstanceCreationEvent WITHIN 10 WHERE TargetInstance ISA 'Win32_USBControllerDevice'");

  ManagementEventWatcher watcher = new ManagementEventWatcher(query);
  Console.WriteLine("Waiting for an event...");

  ManagementBaseObject eventObj = watcher.WaitForNextEvent();

  Console.WriteLine("{0} event occurred.", eventObj["__CLASS"]);

  // Cancel the event subscription
  watcher.Stop();
  return;
  }
  catch(ManagementException err)
  {
  MessageBox.Show("An error occurred while trying to receive an event: " + err.Message);
  }
  }
  }
}


Also here is some useful links:
http://dotnetslackers.com/community/blogs/basharkokash/archive/2008/03/15/USB-Detection-source-code.aspx 
http://www.developerfusion.com/forum/thread/53237/

Any help will be appreciated.

Best Regards, Konstantin.

[PhillipBrooks]

A search of the NI forums for "USB Event notification" returned an entry that may help you:

Windows device event notification

Message Edited by Phillip Brooks on 12-01-2008 06:49 AM

[PhillipBrooks]

I couldn't look at your code initially, I usually work on a LabVIEW 7.0 machine.

You may want to look at the .NET PowerModeChanged Notifier example I coded some time ago.  It's been used by others, and should help you understand how to capture .NET events and convert them to LabVIEW events...

[chrisger]

Hi there

.NET events and LabVIEW aren't working together in most cases. I redraw your C# code, seems to work (see attachment). You have to wait a few seconds for the event to arrive.

[Crowbar]

Hi,chrisger, thanks for help. Could you resave the VI into 8.2 version? About .NET events: may be there are some problems with delegating from LV side etc.

[chrisger]

there you are...