catchevent parameters?

[scriptless]

So I am trying to pass a variable with an event.. Not sure if it's possible? Or if I am way wrong on how to do it? I am planning to have let's say 10 images, and clicking on them will make the player chat the number of the image it clicked on..

PHP Code:

//#CLIENTSIDE
function onCreated() {
  for ( i = 0; i < 10; i++ ) {
    new GuiShowImgCtrl("test" @ i) {
      y = 55;
      x = 50 + i * 40;
      image = "block.png";
      thiso.catchevent(this, "onMouseDown", "onSelect", i); 
    }
  }
}
function onSelect() {
  player.chat = "a" SPC params[0];
} 


Didn't work.

Removing i from catchevent(), however, shows the name of the Control.