Detect user activity

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Hi,

I want an app that I'm writing to be able to hide itself whenever it hasn't
been used for say 10 minutes.

Is there a smart way to detect user activity within an app. Kind of overall
message that I can hook up to so that I dont have to call some function to
register user activity in all my gui event handlers.

Jesper.

[Peter Duniho]

Re: Detect user activity

On Mon, 17 Nov 2008 03:55:01 -0800, Jesper, Denmark
<JesperDenmark@ discussions.mic rosoft.comwrote :

I want an app that I'm writing to be able to hide itself whenever it
hasn't
been used for say 10 minutes.
>
Is there a smart way to detect user activity within an app. Kind of
overall
message that I can hook up to so that I dont have to call some function
to
register user activity in all my gui event handlers.

You first need to define what it means to be "used". Window messages come
into an thread on a regular basis, even when that thread isn't actually
being "used" by the user, at least by conventional definitions of "used".
Repaint messages, system status messages, etc. all occur even when the
program's own features aren't specifically being used.

One possible approach would be to override the Control.WndProc () method,
watching for messages like WM_KEYDOWN, WM_LBUTTONDOWN, etc. This is
probably the most centralized approach, but it does still mean creating a
list of messages that you consider to qualify as your program being
"used". Alternatively, as you suggest you could of course decide in your
program what methods are called as a result of user input, and include
code in those methods to restart the timer when they are called.

The latter approach is likely to match the true semantics of "used" in
your program, but the former is probably easier to maintain and could work
reasonably well. But again, it all depends on what your definition of
"used" is. If you have some less-conventional definition, it might
require yet a different approach than either of those two.

Pete

[Jani Järvinen [MVP]]

Re: Detect user activity

Hi Jesper,

I want an app that I'm writing to be able to hide itself whenever it
hasn't
been used for say 10 minutes. Is there a smart way to detect user
activity within an app?

I'm on the same lines as Peter; you would first need to define what you mean
by "using" your application. However, I've built several Windows
applications that needed a similar feature, and back then I used to define
the "using" as pressing keys and clicking the mouse. That used to be
accurate enough for my needs.

Depending on the application type you have (WinForms?), you could monitor
the messages important to you, and then have a timer (say) to checked
whether an inactivity counter has passed the ten minute limit. If it has,
then you could do something, for example close down network/database
connections, etc.

In WinForms forms you have the KeyPreview property, which helps with the
keyboard events. For the mouse I'm not aware of a similar, easy to use
feature, but you could create an application (Win32) hook to catch the mouse
messages centrally.

Hope this helps!

--
Regards,

Mr. Jani Järvinen
C# MVP
Vantaa, Finland
janij@removethi s.dystopia.fi

http://www.saunalahti.fi/janij/