How to throttle the speed of an event without using Rx Framework

Question

I want to throttle the speed of an event, How I can achieve this without using Microsoft Rx framework. I had done this with the help of Rx. But what I am trying is, I need to throttle Map's View changed event based on a time slot. Is it possible to implement the same without using Rx.

I am not allowed to use Rx and I have to keep the binary size as small as possible.

Answer 1

This works, if your event is of type EventHandler<EventArgs> for example. It creates a wrapper for your event handler that is throttled:

private EventHandler<EventArgs> CreateThrottledEventHandler(
    EventHandler<EventArgs> handler, 
    TimeSpan throttle)
{   
    bool throttling = false;
    return (s,e) =>
    {
        if(throttling) return;              
        handler(s,e);
        throttling = true;
        Task.Delay(throttle).ContinueWith(_ => throttling = false);
    };
}

Attach like this:

this.SomeEvent += CreateThrottledEventHandler(
    (s,e) => Console.WriteLine("I am throttled!"),
    TimeSpan.FromSeconds(5));

Although, you should store the handler returned from CreateThrottledEventHandler if you need to unwire it with -= later.