keybd_event() calls not sending to remote desktop

2
votes

I am trying to use keybd_event() to press certain keys through to a remote desktop application. For the simplest test I am simply opening notepad in the remote session, and have the call keybd_event() run on the local computer with the current user focus on notepad.

Unfortunately it does not appear to be sending any input through to remote desktop.

If I run the application on the local computer with a local instance of notepad in focus, it types exactly what I want to type no problem.

Does anyone have any ideas why this won't work? Obviously I can type manually into the remote desktop session.

Thanks

1
c++winapiremote-desktop
Right click and try running your program as administrator? I had a problem sending key events and mouse events to task manager and running as admin worked. – Brandon
Thanks for the response Brandon, unfortunately we've tried that to no avail. – Raiden616
Have you tried other remote desktop programs? (for example, TeamViewer) It is usual to have problems with standard RDP, but other programs often haven't such strange limitations. – Ilya
Thanks @Ilya, unfortunately that's not possible as we are remoting into a supplied PaaS server. So in essence, we HAVE to use RDP... – Raiden616
Hmm it's weird that it doesn't register the input.. I can't test it as I don't have another computer handy atm.. However, you could try using SetWindowsHookEx and remove the LLKHF_INJECTED flag: msdn.microsoft.com/en-us/library/windows/desktop/… Maybe then it would register as a hardware event and go through. Though, I'm not sure if that actually is the issue. – Brandon

1 Answers

1
votes

Any Remote Desktop program is a gateway to connect a remote system, it is a mediator. Sending any keyboard message to this program via any method (like keybd_event, SendInput, PostMessage etc.) will be silently absorbed by the RDP program. It simply wont consume it, and wont pass it to the connected resource.

Most probably (which I am not sure of), the program might have documented APIs to send some messages to it, like close-session, open-session, or to send-message-to-connected session. Using given API (function, COM interfaces whatsoever), you may send some input to connected resource.