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POFailed to Understand the Use of Delegates in Real World Scenarios
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  1. POFailed to Understand the Use of Delegates in Real World Scenarios
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    copied!<p>I can't understand the proper use of delegates in .NET world. What can't be solved with Delegates? I want to know what scenario/situation is ideal or candidate for delegate usage. </p> <p>I know LINQ and Lambda expressions all use Delegates behind the scenes. I know how to create and consume it but what I have failed to understand is WHY I should create and use them?</p> <p>Any real world example or experience sharing would be highly appreciated.</p> <p>Update:</p> <p>I have created following classes </p> <pre><code>using System; using System.Collections.Generic; using System.Linq; namespace Basics { public class Program { static void Main() { Flight.FlightTakeOffDelegate flightDelegate; var flights = new List&lt;Flight&gt; { new Flight {Number = "FL001", DepartureTime = DateTime.Now, TotalCrew = 15}, new Flight {Number = "FL002", DepartureTime = DateTime.Now.AddHours(1), TotalCrew = 15}, new Flight {Number = "FL003", DepartureTime = DateTime.Now.AddHours(2), TotalCrew = 15}, }; var tower = new FlightTower(flights); // Flight 002 asking to Take off var flightAskingToTakeOff = flights.FirstOrDefault(x =&gt; x.Number == "FL002"); if (flightAskingToTakeOff != null) { Console.WriteLine(string.Format("Flight {0} \t: Okay to take off?", flightAskingToTakeOff.Number)); flightDelegate = tower.CanTakeOff; flightAskingToTakeOff.CanTakeOff = flightDelegate.Invoke(flightAskingToTakeOff); Console.WriteLine(string.Format("Flight Tower \t: {0}", flightAskingToTakeOff.CanTakeOff)); } // Flight 001 asking to Take off flightAskingToTakeOff = flights.FirstOrDefault(x =&gt; x.Number == "FL001"); if (flightAskingToTakeOff != null) { Console.WriteLine(string.Format("Flight {0} \t: Okay to take off?", flightAskingToTakeOff.Number)); flightDelegate = tower.CanTakeOff; flightAskingToTakeOff.CanTakeOff = flightDelegate.Invoke(flightAskingToTakeOff); Console.WriteLine(string.Format("Flight Tower \t: {0}", flightAskingToTakeOff.CanTakeOff)); } Console.ReadKey(); } } public class FlightTower { private readonly List&lt;Flight&gt; _schedule; public FlightTower(List&lt;Flight&gt; schedule) { _schedule = schedule; } public bool CanTakeOff(Flight flight) { var arrivingFlights = _schedule.Where(x =&gt; x.ArrivalTime == DateTime.Now); if (!arrivingFlights.Any()) { var flightInQueue = _schedule.FirstOrDefault(x =&gt; x.DepartureTime == _schedule.Min(c=&gt; c.DepartureTime)); if (flightInQueue != null &amp;&amp; flightInQueue.Number == flight.Number) { return true; } } return false; } } public class Flight { public delegate bool FlightTakeOffDelegate(Flight flight); public string Number { get; set; } public DateTime DepartureTime { get; set; } public DateTime ArrivalTime { get; set; } public int TotalCrew { get; set; } public bool CanTakeOff { get; set; } } </code></pre> <p>}</p> <p>Can anyone please have a look to see how can delegates be used in such scenario??</p>
 

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