How to get useful Windows device information in VBA

Here are (at least) 3 properties of hardware like hard disks (whether they are HDD, SSD, USB or else), printers or anything else that Windows considers a device. These can be very useful to obtain in applications that manage enterprise assets like data and documents:

  • Vendor name,
  • Vendor ID,
  • and serial number.

These hardware properties allow us to uniquely an reliably identify a physical device.

Unfortunately, they’re not so easy to obtain. Particularly if we develop our applications with the “high level” languages that we use in database management systems like Microsoft Access (but also WinDev or FileMaker to name a few others), or in development environments that do not have the necessary, production ready, components or libraries to interact with the system.

Then there are different technologies we can use to get to these hardware properties, like:

  • Windows Management Instrumentation (or WMI), which has already morphed into MI; it is feature rich and COM/ActiveX friendly, but – boy – what a learning curve and a maintenance nightmare threat that would be, just do such a simple thing;
  • .NET, although it would be like using a cannon to kill a mosquito to fire up the .NET runtime engine just to use a nugget of its capacities to bring this small functionality to applications that are not .NET based.
  • The venerable and almighty Win32 API, that we’ll use here from C, to bridge its functionality to Visual Basic, because the Win32 API is mostly C/C++ friendly; my winner here, attaboy.

So, let’s start at the end (!), because we want to get into action immediately, don’t we ?
Some explanation will follow later in this post.

Just before jumping there, let me point out where I am going with all this stuff next:

  • We’re going to combine this code in an out of process, Visual Basic 5 ActiveX EXE server. That will allow us to detect when a USB (or other device type) is plugged or unplugged into the system, in real time;

  • That’s for a bit later, we have some other things to talk about first, but I can’t resist the urge to spoil it:
    using a similar technique (the ActiveX OOP EXE server), we’ll turn Access into a (local machine/network) Web server (whaaat ?!? – Yes, no apache, nginx, node, or whatever needed!)

Watch the (short) demo video

Get device information from an access database demo

Download

  • binaries

    • deviceinfo.dll (32bits version, MD5 sum: fb86ea314cdc4b2fd42f01b3876230d3)
    • deviceinfo64.dll (64bits version, MD5 sum: c27ce08c1c7d982bc475181d6f1cc613)
  • C DLL source code on my github

  • Access Demo database

    • deviceinfo_dll.accdb (contains the MDeviceInfo.bas module with the necessary declares, and additional wrapping to easily use the DLL with one function call and a supporting Type definition).
      Important note: copy the two DLLs (deviceinfo.dll and deviceinfo64.dll) in the same directory where you put the demo database deviceinfo_dll.accdb. The DLLs have to be in one of your PATH directories, or in the same directory of the application using them.

Some (quick) explanation

We can see the VB/A declarations that import the DLL functions in the declarations section of the MDeviceInfo.bas module:

Get to one API function

Instead of crippling our code with calls to each of the DLL functions, we can create one single function that does it all:

This way, we don’t have to worry about forgetting to call the DICreateDeviceInfo() and DIDestroyDeviceInfo() functions that are necessary for the DLL to do its job without crashes.

We gather the retrieved device information in an easy to access structure, in the following (public) Type definition:

Another way of doing it is using a class module. We’ll do that in the next post, where we set up the ActiveX OOP EXE server that will notify us of the devices arrival/removal in real time.

Sample usage

Take a look at the demo() procedure in the MMain.bas module:

About commercial use

If you’re following me thru this coding journey in my latest posts, you’ve probably noticed that I’m putting out all of the code and other assets under either the MIT or the GPL v2 licenses. While the works under the MIT license are completely free to use in all scenarios (commercial or not), that’s not true for works under the GPL v2 license, where you have to give these assets or your derived ones back to the community or whomever you distribute it.

Talking about the journey, if you’re wondering why I’m starting to making code and posts rain in these days (well, I mean, considering my personal publishing scale), allow me to give you a hint: I’ve started my sole ownership company as an independent software developer, back in may 1995…

So, I’m however going to set up a dual licensing system, so you can reuse the code/assets I publish here (or thru devinfo.net), in your commercial applications without worries. I know one buck has not the same value depending on our situation or where we live. Fear not, I can’t make specific promises for now, but I’ll do my best to be fair and affordable for everyone, leaving open the option to paypal me for a coffee or a beer, or just leave a donation (on which I’ll give back somehow), when it is reasonable.

Anyway, if you made it thru here, thank for your attention, don’t hesitate to share a link to this post where you see fit, open or join the conversation here, or drop me a tweet (I’m @francescofoti), I’ll always appreciate that.

And see you soon, because we’re not done yet đŸ˜‰