11.1 委托实例 Action 与 Func

Action 和 Func 是 C# 内置的委托实例，它们都有很多重载以方便使用。

    class Program
    {
        static void Main(string[] args)
        {
            Calculator calculator = new Calculator();
            Action action = new Action(calculator.Report);
            calculator.Report();//直接调用Report方法
            action.Invoke();//间接调用Report方法
            action();//简便写法
            Func<int, int, int> func1 = new Func<int, int, int>(calculator.Add);
            Func<int, int, int> func2 = new Func<int, int, int>(calculator.Sub);
            int x = 100;
            int y = 200;
            int z = 0;
            //z = func1.Invoke(x, y);
            z = func1(x, y);
            Console.WriteLine(z);
            //z = func2.Invoke(x, y);
            z = func2(x, y);
            Console.WriteLine(z);
        }
    }
    class Calculator
    {
        public void Report()
        {
            Console.WriteLine("I have 3 methods.");
        }
        public int Add(int a,int b)
        {
            int result = a + b;
            return result;
        }
        public int Sub(int a, int b)
        {
            int result = a - b;
            return result;
        }
    }