Event Listener not tiggered

programming flash
1

i a progress event listening in a progressbar that is in side a movie clip (test_mc.progressBar) When the progress bar is complete the event listener is not trigged…the code is below.

addEventListener(ProgressEvent.PROGRESS, whenDone);

function whenDone(event:ProgressEvent):void {
        if(test_mc.progressBar.width == 50){
        work_txt.text = "work";
        }
}
        
whenDone(null);