C#•2y ago

✅ Detect key press outside of the form

Hello i'm working with c# windows forms. My form has a transparent panel that i can click and see through. How can i capture the key pressings when not focused on the main form ??

qqdev•2/21/24, 3:33 PM

Used to accomplish that with a global keyboard hook

qqdev•2/21/24, 3:33 PM

Not sure if that's still the way to go

qqdev•2/21/24, 3:34 PM

Spoiler: It is kinda nasty when you are not familiar with that kind of stuff

MotherBrokerOP•2/21/24, 3:34 PM

I've seen both global keyboard hook as well as GetAsynckeystate dll import from user32 but isn't there actually a simpler way ? in c++ there's already the GetAsyncKeyState function ?

qqdev•2/21/24, 3:34 PM

Wait. Your form is transparent

Qqqdev Wait. Your form is transparent

MotherBrokerOP•2/21/24, 3:34 PM

no only the panel

qqdev•2/21/24, 3:35 PM

Do you have a screenshot?

MotherBrokerOP•2/21/24, 3:35 PM

purple part is the panel that's transparent and black part is a picturebox. The red part is the main form that's not transparent

qqdev•2/21/24, 3:36 PM

And you want to capture inputs within that transparent part?

qqdev•2/21/24, 3:36 PM

Or in general

MotherBrokerOP•2/21/24, 3:38 PM

It's like a cardboard box with a rectangle hole and you can see what's behind it. The picturebox displays modified images with OpenCV of what is inside the purple part. I need to still be able to click and see through but at the same time capture which key is being pressed

MotherBrokerOP•2/21/24, 3:38 PM

(if it ain't so clear i'll try to re-explain lol)

leowest•2/21/24, 3:39 PM

out of curiosity what is that for?

leowest•2/21/24, 3:39 PM

like what are u capturing etc

Lleowest out of curiosity what is that for?

MotherBrokerOP•2/21/24, 3:39 PM

It's like a "screenshare" but the picturebox will display the shapes that OpenCV can detect (circle in my case)

MotherBrokerOP•2/21/24, 3:40 PM

And i want to detect where is my mouse cursor when i click in the purple part

leowest•2/21/24, 3:41 PM

even if the form is not in foreground?

leowest•2/21/24, 3:41 PM

or it will be always in foreground

Lleowest even if the form is not in foreground?

MotherBrokerOP•2/21/24, 3:41 PM

the form is topmost so you will always have this box to see the output and what you're capturing

leowest•2/21/24, 3:41 PM

top most but not active window I guess

leowest•2/21/24, 3:41 PM

if that is even possible

MotherBrokerOP•2/21/24, 3:42 PM

And i need to retrieve the X, Y coords of the mouse when i press a key (or mouse click)while in the purple part

leowest•2/21/24, 3:42 PM

I guess u would have to globaly track the mouse and use your window position minus screen size to get he mouse position I wonder if there is anything that facilitates that

leowest•2/21/24, 3:42 PM

I suppose u already tried tracking it from the form itself right?

MotherBrokerOP•2/21/24, 3:44 PM

I didn't understand sorry lol, i didn't try any stuff for now cause i want a simple solution and not use overcomplicated stuff

MotherBrokerOP•2/21/24, 3:44 PM

the code is already a bit heavy and i don't want my brain to melt for capturing inputs xd

leowest•2/21/24, 3:45 PM

well if the for is always active, this is winforms?

MotherBrokerOP•2/21/24, 3:45 PM

wdym this is windforms ?

leowest•2/21/24, 3:45 PM

nvm u said in your question windows formswindows forms

qqdev•2/21/24, 3:45 PM

Yeah, I don't think you can click through while also getting notified about the input. Global stuff needed

MotherBrokerOP•2/21/24, 3:45 PM

The form doesn't have the focus when i click through

leowest•2/21/24, 3:46 PM

yeah then it wont be trivial

MotherBrokerOP•2/21/24, 3:46 PM

Damn, goofy c#

leowest•2/21/24, 3:46 PM

I mean its not c# thou

leowest•2/21/24, 3:46 PM

its just how windows work

MotherBrokerOP•2/21/24, 3:46 PM

Yeah true but there should be some stuff made to avoid situations like this

MotherBrokerOP•2/21/24, 3:47 PM

Thanks for the help guys, i'm gonna do my research about user32 getasynckey

qqdev•2/21/24, 3:47 PM

Maybe, but it is veeeeery specific

qqdev•2/21/24, 3:47 PM

And not sure if possible at all

Qqqdev Maybe, but it is veeeeery specific

MotherBrokerOP•2/21/24, 3:47 PM

Yes but global key capturing is pretty common

leowest•2/21/24, 3:48 PM

but u can probably track the purple part

leowest•2/21/24, 3:48 PM

let me try

MotherBrokerOP•2/21/24, 3:49 PM

Alright thanks

leowest•2/21/24, 3:49 PM

yeah you can use MouseMove event on the panel

leowest•2/21/24, 3:49 PM

it still captures it even with the window not being active but topmost

leowest•2/21/24, 3:50 PM

so all u would need is a win32api to get the left mouse press

leowest•2/21/24, 3:50 PM

and store both

leowest•2/21/24, 3:50 PM

so it would be that difficult

MMotherBroker Yes but global key capturing is pretty common 😦

qqdev•2/21/24, 3:50 PM

That's true. I think it's hard to bring into any offical .NET codebase because you would have to make it cross-plat and WinForms, etc. don't get that many new features (lol) ;D

Lleowest yeah you can use MouseMove event on the panel

MotherBrokerOP•2/21/24, 3:51 PM

So you said i can retrieve the mouse coords even if transparent but for the detection of key i need to go with something different ?

✅ Detect key press outside of the form

Similar Threads

Similar Threads

Similar Threads