XNA TimeAction class

using System;
using Microsoft.Xna.Framework;

namespace BaseXNAGameLibrary.Utils
{
    /// <summary>
    /// Performs an action over a specified amount of time.
    /// The action is an optional Action delegate,
    /// if not set this class simply serves as a mechanism of notifying another class when a certain amount of time has passed.
    ///
    /// Author: Nick Vanheer, immersivenick.wordpress.com
    /// Feel free to extend and let me know if you've made it more powerful!
    /// </summary>
    public class TimeAction
    {
        TimeSpan time = TimeSpan.FromSeconds(1);
        TimeSpan timeSoFar = TimeSpan.Zero;

        bool isLoop = false;

        public float LerpAmount { get; private set; } /* value between 0 and 1 indicating the current progress (0 = start, 1 = end)  */

        /// <summary>
        /// Instantiates a new TimeAction object
        /// </summary>
        /// <param name="time">The time after which something needs to happen</param>
        /// <param name="loop">Repeats the action over the specified time interval</param>
        public TimeAction(TimeSpan time, bool loop = false)
        {
            this.time = time;
            this.isLoop = loop;
        }

        /// <summary>
        /// Updates the TimeAction class and executes an optional action after the time interval has been met
        /// </summary>
        /// <param name="gt">The current GameTime</param>
        /// <param name="a">An Action delegate to perform after the specified time has been elapsed (optional)</param>
        /// <returns></returns>
        public bool Update(GameTime gt, Action a = null)
        {
            if (timeSoFar < time)
            {
                timeSoFar += gt.ElapsedGameTime;

                if (timeSoFar >= time)
                {
                    if(a != null)
                        a();

                    if (isLoop)
                        timeSoFar = new TimeSpan(0, 0, 0);
                    else
                        timeSoFar = time;

                    return true;

                }

                LerpAmount = (float)timeSoFar.Ticks / time.Ticks;

                return false;
            }

            return false;
        }
    }
}