SendInput on a remote process?

[tony74]

I'm trying to do a workaround for an app that doesn't have any command line options.

In this case, I would need to 'tab' to a checkbox, click it, then 'tab' to a 'start' button and click that - in a remote running process, that I spawned from my main program using ShellExecute, since CreateProcess would wait 'till it closed, which doesn't let me operate on it (which may not be possible, anyway).

Sounds like one of those 'You can't get there from here' situations.

Maybe this isn't a doable thing.
Maybe I'm not using SendInput correctly (after all, I have no experience with it).

But, MrAutoHotkey does it from his runtime, so I still hold out hope I can do this internally without resorting to any additional external processes ( himmel, I'm *already* an 'external' process! ).

There's no error message from SendInput.
But here's what appears on the command line after I exit:

Code: [Select]

C:\Programming\proto>"BlockInput function (winuser.h) - Win32 apps _ Microsoft Learn_files"

Which is a tab in my browser...
So it looks like SendInput is, indeed, working on at least *one* remote process...
Just not the one I want it to.

Here's what I do after the external program is up and running:

Code: [Select]

void robodim(void)
{
    char buf[1024];
    INPUT inputs[6] = {0};
    ZeroMemory(inputs, sizeof(inputs));
   
    //Press tab
    inputs[0].type = INPUT_KEYBOARD;
    inputs[0].ki.wVk = VK_TAB;
   
    //lift key
    inputs[1].type = INPUT_KEYBOARD;
    inputs[1].ki.wVk = VK_TAB;
    inputs[1].ki.dwFlags = KEYEVENTF_KEYUP;

    //press tab agin
    inputs[2].type = INPUT_KEYBOARD;
    inputs[2].ki.wVk = VK_TAB;
   
    //lift key
    inputs[3].type = INPUT_KEYBOARD;
    inputs[3].ki.wVk = VK_TAB;
    inputs[3].ki.dwFlags = KEYEVENTF_KEYUP;

    //press spacebar to check
    inputs[4].type = INPUT_KEYBOARD;
    inputs[4].ki.wVk = VK_SPACE;
   
    //lift key
    inputs[5].type = INPUT_KEYBOARD;
    inputs[5].ki.wVk = VK_SPACE;
    inputs[5].ki.dwFlags = KEYEVENTF_KEYUP;


    UINT uSent = SendInput(ARRAYSIZE(inputs), inputs, sizeof(INPUT));
    if (uSent != ARRAYSIZE(inputs))
    {
        sprintf(buf,"SendInput failed: 0x%x\n", GetLastError());
        MessageBox(NULL,buf,"",MB_OK);
    }
}

After which I exit.

That's all I got, Thanks.

[MrBcx]

Here's a different look at the problem.

When compiled and run at a command prompt, it will launch NOTEPAD

Code: [Select]


#include <windows.h> 
 
void MySendkey (unsigned char vKey)
{
  keybd_event(vKey,0,KEYEVENTF_EXTENDEDKEY,0);
  keybd_event(vKey,0,KEYEVENTF_EXTENDEDKEY|KEYEVENTF_KEYUP,0);
}

 

int main(int argc, char *argv[])
{
  MySendkey(VK_N);
  MySendkey(VK_O);
  MySendkey(VK_T);
  MySendkey(VK_E);
  MySendkey(VK_P);
  MySendkey(VK_A);
  MySendkey(VK_D);
  MySendkey(VK_RETURN);
  return EXIT_SUCCESS;   
}



[TimoVJL]

Should remote app have to have a focus before filling keyboard buffer ?

[MrBcx]

Should remote app have to have a focus before filling keyboard buffer ?

Yes ... absolutely.

[tony74]

@MrBCX

The example differs a bit from my use-case.

The program I'm using launches an external program through ShellExecute.
ShellExecute, rather than CreateProcess, is used so the call, as much as possible, emulates a user having called the external from Explorer or the desktop.

The external program does have focus upon execution, as far as I know.
Now that the external is up and running, my program attempts to sendkeys, but I don't know that in sending the keys, the focus doesn't change back to my program rather than the external?

In any case, the keys don't get through to the intended external.

I enumerated the windows and got a handle for the child-window that has the checkbox and start button I need to click.
I haven't yet, but I could setfocus on the retrieved window handle, just to be sure, but what then?

I could sendmessage, but I still haven't found the two control handles I need. Would winSpy be the next step?
Would those handles or ID change if run from another machine?

So many questions, I know. Just looking for a way-in at the moment, trying not to go 'off the rails' following a wrong path.

Thanks to both of you for having a look.

[tony74]

Well, to update, it looks like this is a QT window, so the qwidgit wrapper and 'signals' might throw a new wrinkle into the mix.
I'll try enumerating child windows of the child window tomorrow and see what happens.

WinSpy didn't come up with anything for controls, so we'll see.
And, yeah, these queries have to happen live for each start because handles change every run, which is expected.