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copied!<p>Passing additional parameters for your callbacks is possible via some kind of delegate function or closure. However it is often considered a bad practice. You may use event <code>target</code> property instead to determine your index based on <code>FileReference</code>.</p> <p><strong>Edit:</strong> here is a sample of using closures:</p> <pre><code>function getTimerClosure(ind : int) : Function { return function(event : TimerEvent) { trace(ind); }; } for (var i = 0; i < 10; i++) { var tm : Timer = new Timer(100*i+1, 1); tm.addEventListener(TimerEvent.TIMER, getTimerClosure(i)); tm.start(); } </code></pre> <p>This will continuously trace numbers from 0 to 9.</p> <p><strong>Edit2:</strong> here is a sample of creating a delegate based on a function closure:</p> <pre><code>function timerHandler(event : Event, ...rest) : void { trace(event, rest); } function Delegate(scope : Object, func : Function, ...rest) : Function { return function(...args) : void { func.apply(scope, args.concat(rest)); } } var tm : Timer = new Timer(1000, 1); tm.addEventListener(TimerEvent.TIMER, Delegate(this, this.timerHandler, 1, 2, 3)); tm.start(); </code></pre> <p>However this is a bad approach since unsubscribing for such a listener is a hell pain. This in turn will probably cause some memory leakages, which will decrease overall performance of your application. <em>So, use with caution!</em></p> <hr> <p><strong>Bottom line:</strong> if you know how to work with closures, use them - it is a wonderful thing! If you don't care about your application performance in a long perspective, use closures - it's simple!</p> <p>But if you are unsure about closures, use a more conventional approach. E.g. in your case you could create a <code>Dictionary</code> that matches your <code>FileReference</code> objects to appropriate indices. Something like that:</p> <pre><code>var frToInd : Dictionary = new Dictionary(false); // false here wouldn't prevent garbage collection of FileReference objects for (var i : int = 0; i < 10; i++) { // blah-blah stuff with `lib` objects frToInd[lib.fileRef] = i; // another weird stuff and subscription } function eventListener(event : Event) : void { // in the event listener just look up target in the dictionary if (frToInd[event.target]) { var ind : int = frToInd[event.target]; } else { // Shouldn't happen since all FileReferences should be in // the Dictionary. But if this happens - it's an error. } } </code></pre> <p><em>-- Happy coding!</em></p>

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