using System;

using System.Threading;

​

namespace Events

{

    public class Program

    {

        public static void Main(string[] args)

        {

            Progress p = new Progress();

            p.Start(100, 5);

        }

​

    }

​

    public class Progress

    {

        public EventHandler ProgressStartedEvent;

        public EventHandler<ProgressInfoEventArgs> UpdateProgressEvent;

        public EventHandler ProgressCompletedEvent;

​

        public void Start(int max, int interval = 1, int start = 0)

        {

            if (interval <= 0)

            {

                throw new ArgumentException("The interval parameter must not be less than or equal to 0");

            }

​

            if (start > max)

            {

                throw new ArgumentException(string.Format("The start ({0}) parameter must not be greater than max parameter ({0})", start, max));

            }

​

            OnProgressStarted();

​

            for (int i = start; i <= max; i += interval)

            {

                // Simulate work here

                Thread.Sleep(100);

                OnProgressUpdate(new ProgressInfoEventArgs(i, max));

            }

​

            OnProgressCompleted();

        }

​

        protected virtual void OnProgressStarted()

        {

            EventHandler handler = ProgressStartedEvent;

            if (handler != null)

            {

                handler(this, new EventArgs());

            }

        }

​

        protected virtual void OnProgressUpdate(ProgressInfoEventArgs e)

        {

            EventHandler<ProgressInfoEventArgs> handler = UpdateProgressEvent;

            if (handler != null)

            {

                handler(this, e);

            }

        }

​

        protected virtual void OnProgressCompleted()

        {

            EventHandler handler = ProgressCompletedEvent;

            if (handler != null)

            {

                handler(this, new EventArgs());

            }

        }

    }

​

    public class ProgressInfoEventArgs : EventArgs

    {

        public ProgressInfoEventArgs(double currentProgress, int max)

        {

            double dblMax = (double)max;

            CurrentProgress = currentProgress / dblMax;

        }

​

        public double CurrentProgress { get; set; }

    }

}

​