Emulate Fn key press using keybd_event API or sendkeys class - c#

I have a Fn key on my USB keyboard which allows me to enable certain features on my keyboard. So, if I press Fn + F10, the keyboard will switch to a different mode.
I have a feeling it's possible that Windows has no access to the Fn on my keyboard. However, I thought maybe there may be some undocumented way of triggering this key for keyboard that have a Fn key (like laptops, etc).

Basically, no you can't emulate it.
Keyboards work by sending standard scan codes to the PC. On a regular keyboard each key is mapped to a scan code. There is no scan code for the fn button, instead it tells the keyboard to change the scan code it sends in response to a given key press. E.g. on my laptop the home button normally sends the scan code for home, but if I press the Fn key as well it sends the scan code for print screen. It is deliberately transparent to the operating system.

Related

Windows Forms: simulate holding key down on keyboard

During my search, I've seen many different versions of this question, yet somehow none of the solutions provided solved my problem.
It's really quite simple, I just want to simulate holding down a key on the keyboard through code. I want to try and make a character in a game walk forward constantly, so I just need to make a program that simulates holding down the 'W' key. I've seen a lot of people were using Windows Forms for this, I don't know if it actually is the right application but if it works I'm happy.
Just very quickly sending the key doesn't work, so simply calling SendKeys.Send('W') every 30ms does not make my character move in-game. So, what can I do to simulate holding down a key on the keyboard?
Here you go, a .Net library can simulate key press
https://inputsimulator.codeplex.com/
Edit
To get the key works, the external program must in active window, and your program need to run in background.
Windows Forms provides the SendKeys method which can simulate text
entry, but not actual key strokes. Windows Input Simulator can be used
in WPF, Windows Forms and Console Applications to synthesize or
simulate any Keyboard input including Control, Alt, Shift, Tab, Enter,
Space, Backspace, the Windows Key, Caps Lock, Num Lock, Scroll Lock,
Volume Up/Down and Mute, Web, Mail, Search, Favorites, Function Keys,
Back and Forward navigation keys, Programmable keys and any other key
defined in the Virtual Key table.
It provides a simple API to simulate
text entry, key down, key up, key press and complex modified key
strokes and chords.

SendKeys alternatives?

I created a keypad app that stays on top, but does not take the focus so that on a touch screen it will forward whatever keys you press to the active application via SendKeys.
It works perfectly with every application I have tried it with... except, of course, for the one I actually need it to work with which is a Point Of Sale application. The POS application lets the user type in item codes on the keyboard but it doesn't have a good keypad for touchscreens so that's why I'm trying to create an external one for it (since I don't have access to the POS application code).
It actually does work when you first try it, but then it's pretty sporadic. Using the keyboard directly always works, so I'm not sure why SendKeys only works sometimes with this application. I've tried implementing it several ways... sending the keys as they are pressed, sending them altogether when the user presses the enter button on the keypad, copying the keys to the clipboard and then using send keys to do a Ctl-V and then Enter.
What other options do I have to simulate a key press to another application? SendKeys doesn't seem to perfectly simulate key presses, so is there a lower level mechanism I can tap into?
I should mention that when it doesn't work, what happens is that I get a beep from the POS application as though I'd pressed an invalid key. So it's not that it isn't getting some kind of input but clearly it isn't getting the key I'm sending it the same way it would from an actual keyboard.
I found this Windows Input Simulator: https://inputsimulator.codeplex.com/
Super easy to use and way, way, way better than SendKeys. And as a bonus, in addition to letting you simulate input, it also lets you set low level keyboard/mouse hooks.

How can I simulate function key combinations using C#?

I was hoping someone could help me with simulating a function key combination in C#, in this case FN + F4.
Here's what I'm trying to do... I have an older touchscreen netbook that I recently installed Windows 8 on. It has a swivel screen so you can fold it down and use it like a tablet. Windows 8 runs surprisingly well on it. I had a few minor issues, most of which I was able to work out, but one remains.
When you first power up the netbook or wake it from sleep, the screen is at 30% brightness, and Windows thinks that this is the max setting, so increasing the screen brightness through the normal methods does not work. On my netbook, pressing FN + F4, restores the screen to full brightness. This is a minor annoyance though, because I have to swivel the screen back and forth to fix the brightness using the physical keyboard, when I'd like to just leave it in the tablet position and minimize wear and tear.
What I'd like to do is write a little application that runs on start up, and simulates the function key combination, so the brightness is restored automatically. Any suggestions would be greatly appreciated. Thanks.
The Fn key is not a key that is sent from the keyboard to the computer. It is actually used to change the meaning of keys on the keyboard (such that the keyboard sends different scancodes when the key is pressed with Fn held down).
You should be able to easily write a simple Windows Forms program that listens to key presses and shows you what has been received. Register for the KeyDown event. The KeyEventArgs your handler receives has various properties that you can inspect to see what is being received.
The FN key isn't a real keyboard key like the other modifiers (shift, alt, ctrl) nor is it a function key like the F1 - F12. The FN key is a hardware only key that simply tells the hardware to send a different keystroke while the FN key is being pressed.
So, you are going to have to adjust the brightness manually like "m-y" stated in the comments or through some other mechanism.
Reference Link.

Detect pressed key on Desktop

I want to know how can i detect which key pressed (for example on Desktop or my computer ).
when detect pressed key show it with MessageBox
how can i do this?
Detecting the key presses outside of your application requires installing a Low Level Keyboard Hook. Here is a CodeProject article demonstrating the process.

Emulate held down key on keyboard?

I know SendKeys can emulate typing and send individual keystrokes but I'm looking for a way to emulate holding down a key. My goal is an app that acts as a joypad for a windowed game. Imagine holding a tablet PC and having arrow keys and basic buttons on either side of the screen and pressing them emulates keyboard presses which a game then receives. That's my goal.
When a finger presses down on a button, I want to translate that to pressing down on a keyboard key. Upon releasing that button, I want to release that key. I know this'll probably require some low level code and I'm ok with that.
NOTE: I do NOT want to emulate these events in my own app, but system wide. I'm writing this for an XNA game of mine and it's not listening for direct, focus key events, it's checking the state of the keyboard, (as I assume most games do) and responding to that. I want my app to trick my game into thinking a key is held down at the proper times.
If you want to emulate it system-wide, you can use SendInput from Core.dll. There are more detailed information on how to do that here.
However, it is very rare, that you will actually need that. Instead, you should try to manipulate with only your own app (it seems more like that is what you need in this case). You can simply just make variables for all the keys, you want to read, and then read those variables from both keyboard AND tablet.
EDIT
oh, this link will probably be better...

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