Set a hook to intercept WM_COMMAND sent from a menu

Posted on 2004-10-14
Medium Priority
Last Modified: 2008-01-09

I have an ActiveX DLL which is loaded by an application (MSN Messenger) in the same thread. I want the DLL to know when the button "Send File" in the application is pressed.

Using Spy++, I've found that it generates this message when the button is pressed:
000C044A P WM_COMMAND wNotifyCode:0 (sent from a menu) wID:40275 [wParam:00009D53 lParam:00000000]

How can I intercept that message from the DLL?

I've tried WH_MSGFILTER and WH_GETMESSAGE hooks but they do not seem to fire when the button is pressed. Any ideas?
Question by:ricardog2
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
LVL 17

Expert Comment

ID: 12320124
>>but they do not seem to fire when the button is pressed.
Are you sure the hook installs correctly? I'm not sure if the application would have access to a procedure in your EXE or not.

Alternatively, you can try to cross-process subclass the actual Button's window to receive the WM_COMMAND.

LVL 17

Accepted Solution

zzzzzooc earned 750 total points
ID: 12320128

Author Comment

ID: 12321721
I've used the examples available at http://www.oreilly.com/catalog/subhookvb/ to install the hooks. I get messages when I click on the menu or drag the window, but I'm not sure which kind of hook is needed to intercept that specific message.

Also, my procedure is in the same thread as the EXE (I've compared the App.ThreadID to the EXE's one listed in Spy++), so it should work without a cross-process hook. Anyway, I'll try that.

Thanks for the answer.
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!


Author Comment

ID: 12322763
I got it working! It really was WH_GETMESSAGE, but the oreilly's example code had to be modified a bit to get the message correctly.

Since I've found the problem with the DLL you've suggested, I'll give you the points.
LVL 17

Expert Comment

ID: 12327828
'grats. Also, in case you haven't gotten to it, you may have the get the high/low bits for wParam (or lParam.. forgot) to know which button notification (BN) was sent (such as BN_CLICKED).

LVL 17

Expert Comment

ID: 12327844
Unless you meant a menu-item instead of a button (doh). Just woke up so I'm a bit dazed.. lol :)

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction While answering a recent question about filtering a custom class collection, I realized that this could be accomplished with very little code by using the ScriptControl (SC) library.  This article will introduce you to the SC library a…
You can of course define an array to hold data that is of a particular type like an array of Strings to hold customer names or an array of Doubles to hold customer sales, but what do you do if you want to coordinate that data? This article describes…
Get people started with the process of using Access VBA to control Excel using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Excel. Using automation, an Access application can laun…
Get people started with the utilization of class modules. Class modules can be a powerful tool in Microsoft Access. They allow you to create self-contained objects that encapsulate functionality. They can easily hide the complexity of a process from…
Suggested Courses

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question