I have an application where I have multiple keyboards connected through USB.
I need to hook a specific keyboard to get the keypress directly into the software, even if this one is not on the foreground. This so far works based on this project. The other keyboards shall work as normal.
Although it seems by using Direct Input, it is not possible to stop propagation (we don't want other apps to get that particular keyboard input).
Concerning Global Hook, it can block the keypress system-wise, but it is impossible, as far as I know, to identify the source of the keystroke (which keyboard it is from) and thus to selectively block them.
There is another project, here, that combines the two, but it is quite messy and heavy.
Is there a better way to achieve this? I am surprised that simple task is so complex.
If you are going to make the app windows only, you should look into Windows raw input api
It isn't that complicated.
Related
I have to write an application in C# that listens to any keys being pressed. In actuality I have a bar code scanner sending the "key pressed" event, and I need to listen it... what it does from there is beyond the scope of my question.
My security requirements are that there is not allowed to be any sign-on to the machine in any way shape or form AND this must run as a windows service. The user will start the machine and walk away (i.e., no desktop session).
I'm assuming I'm going to have to go unmanaged for this.
Given the security requirements is this even possible? If so, any pointers on where to start would be great.
Thanks in advance,
Jay
Try keyboard and mouse hook
http://www.codeproject.com/KB/cs/globalhook.aspx
You will have to learn pInvoke with combination of learning how to look for the right events produced at the lower level of OS. By calling into user32.dll using pInvoke your managed code can filter those events through the hooks.
http://pinvoke.net/default.aspx/user32.SetWindowsHookEx
If you need to see keyboard presses for all apps, system-wide Hooks would be the way to go normally, but the problem is that the security changes in Vista and above make hooks rather less useful. A process cannot hook another process at a higher integrity level, so there's no guarantee you will see all events.
However if you only need to see events going to a particular app - the one reading the bar codes - then provided you can identify that process, a thread-specific hook will suffice and the integrity question will not arise.
My app (in C#) need to interface with a USB bar-code scanner, which is basically working like a keyboard. It inputs the bar-code with an enter key at the end.
The app need to be work even when it's at background, so I am using low level keyboard hook to get and filter the bar-code out in the global key events. This part is already working.
Here is my problem: I don't want other apps to get the keyboard(scanner) inputs if it is a bar-code. And the normal key events should not be interfered. In one word, block the key events selectively. Is this possible?
My app is in C#, but I have no problem with C++ or more native solutions as long as it's easy to integrate in C#.
Thanks.
Additional Information：
The whole idea is working at background, even when it's not active. It watches the global key events stream and spot the bar-code sequence (already implemented with Hook). And most importantly, it do NOT interfere with normal keyboard events nor other applications' operation. That's why I cannot block all the key events or make it top-most.
I already can get the bar-code. I need to prevent other applications from getting the bar-code.
At the end of your keyboard hook you would call CallNextHookEx to execute next hook in the chain.
I would suggest that put some unique signature as a preamble for your barcode so that your keyboard hook procedure can detect it as a valid barcode input from your scanner. Now, when you get this data, just skip the call to 'CallNextHookEx' so that the chain will be discontinued and other programs won't get your barcode. Otherwise - call 'CallNextHookEx' so the chain can continue.
Note: This is my theory, I have never tried the exact same thing myself. I have however, written hooks in C++ and C#.
Check this project out
http://globalmousekeyhook.codeplex.com/
It is in C# as well so will make your coding easier. Sounds like all you need is to hook up the global key press event and suppress it by setting the Handled value or something similar.
I have to write an application in C# that listens to any keys being pressed. In actuality I have a bar code scanner sending the "key pressed" event, and I need to listen it... what it does from there is beyond the scope of my question.
My security requirements are that there is not allowed to be any sign-on to the machine in any way shape or form AND this must run as a windows service. The user will start the machine and walk away (i.e., no desktop session).
I'm assuming I'm going to have to go unmanaged for this.
Given the security requirements is this even possible? If so, any pointers on where to start would be great.
Thanks in advance,
Jay
Try keyboard and mouse hook
http://www.codeproject.com/KB/cs/globalhook.aspx
You will have to learn pInvoke with combination of learning how to look for the right events produced at the lower level of OS. By calling into user32.dll using pInvoke your managed code can filter those events through the hooks.
http://pinvoke.net/default.aspx/user32.SetWindowsHookEx
If you need to see keyboard presses for all apps, system-wide Hooks would be the way to go normally, but the problem is that the security changes in Vista and above make hooks rather less useful. A process cannot hook another process at a higher integrity level, so there's no guarantee you will see all events.
However if you only need to see events going to a particular app - the one reading the bar codes - then provided you can identify that process, a thread-specific hook will suffice and the integrity question will not arise.
Is there a practical way to set the global status message in Pidgin for Windows from .NET?
Dbus is not available in the Windows version of Pidgin.
Searching SO and the net has revealed helpful tips such as "rewrite libpurple in C#", which might be a bit beyond my time/enthusiasm level for this project at least...
Thanks
how about writing a plugin, and have it expose a way for your other program to pass the status to it. Could be a file that you write the status to, or maybe a local tcp port (if you can do that in plugins).
Have you considered simply simulating keyboard input to the Pidgin window using C#?
You will need to find the Pidgin window programmatically and then set your status by sending simulated keyboard input to that window handle.
A good Microsoft example of how it was done with Calculator:
http://msdn.microsoft.com/en-us/library/ms171548.aspx
As I recall, Pidgin will set your status if you simply put the main window (buddy list) in focus, start typing, and then press Enter. Simulating this keyboard input should be quite straightforward.
A dirty solution (that future versions of Pidgin might break), yes, but certainly MUCH easier than writing a plug-in or making your own libpurple wrapper.
I want to send an Application Key Presses, To Automate some stuff that has to be done repeatedly and So I don't always have to cramp my fingers.
In C#, it's nice to use SendKeys.Send(), but this won't work because the Application doesn't take Windows Messages. SendKeys.SendWait() does nothing at all.
How would I STILL Simulate the Keyboard events?
Come To Think of It, I was going to use some P/Invoke to simulate Mouse Events too, but If it takes no messages, How Can I get around that?
EDIT - I can use mouse and keyboard to interact with the program, I just cannot manipulate it with Windows Messages sent from my own Code.
Have you tried AutoIt?
Is it a console app? If so, maybe you should be SendKeys'ing to the command shell instance it is running in.