detect keystate

[warbornster]

Hi, I want to detect wether the arrowkeys are pressed down or not. I
would be happy if it would be as simple like "if (keys.Up == true)
something()" but there seems to be harder than this. I would just like
to detect the state, not start some kind of event. Is it possible ?

[Marc Gravell]

I don't know if there is a managed mechanism for querying random keys
(although Control.ModifierKeys handles Ctrl, Alt, Shift etc); perhaps
need to use P/Invoke?

Untested: (taken from System.Design.NativeMethods)

[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)]
public static extern short GetKeyState(int keyCode);

No idea if this will work, though...

Marc

[Fabio Z]

<wa*********@gmail.comha scritto nel messaggio

Hi, I want to detect wether the arrowkeys are pressed down or not. I
would be happy if it would be as simple like "if (keys.Up == true)
something()" but there seems to be harder than this. I would just like
to detect the state, not start some kind of event. Is it possible ?

If you are on a Control (or form) take a look at the ModifierKeys property.

--
www.neodatatype.net

[Marc Gravell]

Actually, ModifierKeys is public static, so you can use
Control.ModifierKeys even if you are writing a console-only
application (give-or-take a reference). Internally it uses the user32
GetKeyState as previously posted (although declared in a separate
class).

Marc

[Fabio Z]

"Marc Gravell" <ma**********@gmail.comha scritto nel messaggio

Actually, ModifierKeys is public static, so you can use
Control.ModifierKeys even if you are writing a console-only application

You're right.
In effects I don't understand why they put the ModifierKeys into
System.Windows.Forms.
I think it should be better into Environment or something.

[Marc Gravell]

Probably for the same reason that Cache is in System.Web but can (if
you try) be used by other application types; clearly some areas of the
framework just got placed in the pet assembly of the team developing
it, even if its true use was wider than that scope. I don't know how
things work at MS, but possibly due to avoiding delays in the repo
cascade if placing higher? (pure conjecture here...)

Marc

[Fabio Z]

"Marc Gravell" <ma**********@gmail.comha scritto nel messaggio

Probably for the same reason that Cache is in System.Web but can (if you
try) be used by other application types;

And this is right!
System.Web.Cache rappresent the cache for web application, so it is into
system.Web.
But the keys are not a prerogative of windows applications.

[Marc Gravell]

Actually, this *was* the case 1.0/1.1 (which I'll admit is a
*reasonable* reason for this location); in 2.0 you can use it anywhere
a bit more conveniently than the CAB. See KB917411 (note the "More
Information" does not apply in 2.0). In my (limited) opinion this
represents a realisation that this is functionality that it is
desirable to be available at a higher level.

Marc