C#: Triggering an Event when an object is added to a Queue

Question

I need to be able to trigger a event whenever an object is added to a Queue.

I created a new class that extends Q

Answer 1

I just did write up on what I call a TriggeredQueue. It's inspired the answer by Marc Gravell.

You can find my post here: http://joesauve.com/triggeredqueuet

And the Gist here: http://gist.github.com/jsauve/b2e8496172fdabd370c4

It has four events:

• WillEnqueue
• WillDequeue
• DidEnqueue
• DidDequeue

You can hook into any of these like so:

YourQueue.WillEnqueue += (sender, e) => {
    // kick off some process
};
YourQueue.DidEnqueue += (sender, e) => {
    // kick off some process
    // e.Item provides access to the enqueued item, if you like
};
YourQueue.WillDequeue += (sender, e) => {
    // kick off some process
};
YourQueue.DidDequeue += (sender, e) => {
    // kick off some process
    // e.Item provides access to the dequeued item, if you like
};

One neat trick is that you can use the DidDequeue method to kick off some process to ensure that the queue is full by making a web request or loading some data from a filesystem, etc. I use this class in Xamarin mobile apps to ensure that data and images are pre-cached in order to provide a smooth user experience, instead of loading images AFTER they scroll onto the screen (like you might see in Facebook and countless other apps).