Delegate

• Delegate

EventHandler

• Um EventHandler em C# é um delegate que representa um método que manipula um evento.

public class EventSample
    {
        public static event EventHandler<EventArgs> CalculationCompleted;

        public static void RunEventExample()
        {
            CalculationCompleted += EventSample_CalculationCompleted;
            CalculationCompleted += EventSample_CalculationCompleted2;
            RunCalculate();
            Console.WriteLine("*************************************");
            CalculationCompleted -= EventSample_CalculationCompleted;
            RunCalculate();
            Console.WriteLine("*************************************");
            CalculationCompleted -= EventSample_CalculationCompleted2;
            RunCalculate();
        }

        private static void RunCalculate()
        {
            Calculator calculator = new Calculator();
            Console.WriteLine(calculator.Sum(10, 20));
            if (CalculationCompleted != null)
            {
                CalculationCompleted.Invoke(null, new EventArgs());
            }
        }

        private static void EventSample_CalculationCompleted(object? sender, EventArgs e)
        {
            Console.WriteLine("CalculationCompleted");
        }

        private static void EventSample_CalculationCompleted2(object? sender, EventArgs e)
        {
            Console.WriteLine("CalculationCompleted2");
        }

    }