Event Trigger For Key Pressed

Unity does not send Key events using the new Event System.

For reference, here's a list of all supported events.

However, you can still process input events if you are the selected object. They are just not sent through the Event System.

See the implementation of InputField.OnUpdateSelected, for reference. This is how Unitys UI uses keyboard input. You'll notice it's very similar to how the old IMGUI got key events from Event.current. Instead, here they use Event.PopEvent in a while loop instead of calling OnGUI several times per frame.

I'm afraid you need to create simple script and catch the key on Update:

 public void Update()
 {
      if (Input.GetKeyUp(KeyCode.X))
     {
        //do stuff
     }
 }

Input has to be checked every frame in Update. There are different functions available. Some just return the state of a button (down or up) some will return true only the frame a button has been pressed down or up. Buttons have to be defined in the input manager.

There are also functions for reading certain keyboard-keys

Input.GetKey

Input.GetKeyDown

Input.GetKeyUp

In general just look into the scripting reference

A script that toggles a light could look like this:

  // UnityScript (Unity's Javascript)
  function Update()
  {
      if (Input.GetMouseButtonDown(0)) // 0 - left button; 1 - right button; 2 - middle button
      {
          light.enabled = !light.enabled;
      }
  }

Make sure you attach this script to a GameObject that has a Light component attached ;)

The same script in C#:

  // C#
  // FlashLightControl.cs
  using UnityEngine;
  
  public class FlashLightControl : MonoBehaviour
  [
      void Update()
      {
          if (Input.GetMouseButtonDown(0)) 
          {
              light.enabled = !light.enabled;
          }
      }
  }
 

You can write a script that manages the keys like this (js) :

 var key : KeyCode;
 
 function Update () {
     
     if(Input.GetKey(key)) {
                  //here you put the code of your event
     }
  }