Get List of connected USB Devices

Question

How can I get a list of all the connected USB devices on a windows computer?

Answer 1

I know I'm replying to an old question, but I just went through this same exercise and found out a bit more information, that I think will contribute a lot to the discussion and help out anyone else who finds this question and sees where the existing answers fall short.

The accepted answer is close, and can be corrected using Nedko's comment to it. A more detailed understanding of the WMI Classes involved helps complete the picture.

Win32_USBHub returns only USB Hubs. That seems obvious in hindsight but the discussion above misses it. It does not include all possible USB devices, only those which can (in theory, at least) act as a hub for additional devices. It misses some devices that are not hubs (particularly parts of composite devices).

Win32_PnPEntity does include all the USB devices, and hundreds more non-USB devices. Russel Gantman's advice to use a WHERE clause search Win32_PnPEntity for a DeviceID beginning with "USB%" to filter the list is helpful but slightly incomplete; it misses bluetooth devices, some printers/print servers, and HID-compliant mice and keyboards. I have seen "USB\%", "USBSTOR\%", "USBPRINT\%", "BTH\%", "SWD\%", and "HID\%". Win32_PnPEntity is, however, a good "master" reference to look up information once you are in possession of the PNPDeviceID from other sources.

What I found was the best way to enumerate USB devices was to query Win32_USBControllerDevice. While it doesn't give detailed information for the devices, it does completely enumerate your USB devices and gives you an Antecedent/Dependent pair of PNPDeviceIDs for every USB Device (including Hubs, non-Hub devices, and HID-compliant devices) on your system. Each Dependent returned from the query will be a USB Device. The Antecedent will be the Controller it is assigned to, one of the USB Controllers returned by querying Win32_USBController.

As a bonus, it appears that under the hood, WMI walks the Device Tree when responding to the Win32_USBControllerDevice query, so the order in which these results are returned can help identify parent/child relationships. (This is not documented and is thus only a guess; use the SetupDi API's CM_Get_Parent (or Child + Sibling) for definitive results.) As an option to the SetupDi API, it appears that for all the devices listed under Win32_USBHub they can be looked up in the registry (at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ + PNPDeviceID) and will have a parameter ParentIdPrefix which will be the prefix of the last field in the PNPDeviceID of its children, so this could also be used in a wildcard match to filter the Win32_PnPEntity query.

In my application, I did the following:

• (Optional) Queried Win32_PnPEntity and stored the results in a key-value map (with PNPDeviceID as the key) for later retrieval. This is optional if you want to do individual queries later.
• Queried Win32_USBControllerDevice for a definitive list of USB devices on my system (all the Dependents) and extracted the PNPDeviceIDs of these. I went further, based on order following the device tree, to assign devices to the root hub (the first device returned, rather than the controller) and built a tree based on the parentIdPrefix. The order the query returns, which matches device tree enumeration via SetupDi, is each root hub (for whom the Antecedent identifies the controller), followed by an iteration of devices under it, e.g., on my system:
  • Root hub of first controller
  • Root hub of second controller
    • First hub under root hub of second controller (has parentIdPrefix)
      • First composite device under first hub under root hub of second controller (PNPDeviceID matches above hub's ParentIdPrefix; has its own ParentIdPrefix)
        • HID Device part of the composite device (PNPDeviceID matches above composite device's ParentIDPrefix)
      • Second device under first hub under root hub of second controller
        • HID Device part of the composite device
    • Second hub under root hub of second controller
      • First device under second hub under root hub of second controller
    • Third hub under root hub of second controller
    • etc.
• Queried Win32_USBController. This gave me the detailed information of the PNPDeviceIDs of my controllers which are at the top of the device tree (which were the Antecedents of the previous query). Using the tree derived in the previous step, recursively iterated over its children (the root hubs) and their children (the other hubs) and their children (non-hub devices and composite devices) and their children, etc.
  • Retrieved details for each device in my tree by referencing the map stored in the first step. (Optionally, one could skip the first step, and query Win32_PnPEntity individually using the PNPDeviceId to get the information at this step; probably a cpu vs. memory tradeoff determining which order is better.)

In summary, Win32USBControllerDevice Dependents are a complete list of USB Devices on a system (other than the Controllers themselves, which are the Antecedents in that same query), and by cross-referencing these PNPDeviceId pairs with information from the registry and from the other queries mentioned, a detailed picture can be constructed.

Answer 2

You may find this thread useful. And here's a google code project exemplifying this (it P/Invokes into setupapi.dll).