C# event debounce

Question

I\'m listening to a hardware event message, but I need to debounce it to avoid too many queries.

This is an hardware event that sends the machine status and I have t

Answer 1

I ran into issues with this. I tried each of the answers here, and since I'm in a Xamarin universal app, I seem to be missing certain things that are required in each of these answers, and I didn't want to add any more packages or libraries. My solution works exactly how I'd expect it to, and I haven't run into any issues with it. Hope it helps somebody.

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace OrderScanner.Models
{
    class Debouncer
    {
        private List StepperCancelTokens = new List();
        private int MillisecondsToWait;
        private readonly object _lockThis = new object(); // Use a locking object to prevent the debouncer to trigger again while the func is still running

        public Debouncer(int millisecondsToWait = 300)
        {
            this.MillisecondsToWait = millisecondsToWait;
        }

        public void Debouce(Action func)
        {
            CancelAllStepperTokens(); // Cancel all api requests;
            var newTokenSrc = new CancellationTokenSource();
            lock (_lockThis)
            {
                StepperCancelTokens.Add(newTokenSrc);
            }
            Task.Delay(MillisecondsToWait, newTokenSrc.Token).ContinueWith(task => // Create new request
            {
                if (!newTokenSrc.IsCancellationRequested) // if it hasn't been cancelled
                {
                    CancelAllStepperTokens(); // Cancel any that remain (there shouldn't be any)
                    StepperCancelTokens = new List(); // set to new list
                    lock (_lockThis)
                    {
                        func(); // run
                    }
                }
            }, TaskScheduler.FromCurrentSynchronizationContext());
        }

        private void CancelAllStepperTokens()
        {
            foreach (var token in StepperCancelTokens)
            {
                if (!token.IsCancellationRequested)
                {
                    token.Cancel();
                }
            }
        }
    }
}

It's called like so...

private Debouncer StepperDeboucer = new Debouncer(1000); // one second

StepperDeboucer.Debouce(() => { WhateverMethod(args) });

I wouldn't recommend this for anything where the machine could be sending in hundreds of requests a second, but for user input, it works excellently. I'm using it on a stepper in an android/IOS app that calls to an api on step.