1.委托声明

2.委托入门实例

namespace ConsoleApplication1
{
    
    public delegate void methodDelegate(string str);
    class Program
    {
        static void Main(string[] args)
        {
            Student student = new Student();
            Teacher teacher = new Teacher("王老师");
            methodDelegate methodDelegate1 = new methodDelegate(student.getStudentName);
            methodDelegate1 += teacher.getTeacherName; //可以指向不同类中的方法！
            //methodDelegate1 += teacher.getClassName; 指向签名不符的方法时提示错误！
            methodDelegate1.Invoke("张三");
            Console.ReadLine();
        }
    }

    class Student
    {
        private String name = "";
        public Student (String _name)
        {
            this.name = _name ;
        }
        public Student() {}
        public void getStudentName(String _name) 
        {
            if (this.name != "" )
                Console.WriteLine("Student‘s name is {0}", this.name);
            else
                Console.WriteLine("Student‘s name is {0}", _name);
        }
    }

    class Teacher
    {
        private String name;
        public Teacher(String _name)
        {
            this.name = _name;
        }
        public void getTeacherName(String _name)
        {
            if (this.name != "")
                Console.WriteLine("Teacher‘s name is {0}", this.name);
            else
                Console.WriteLine("Teacher‘s name is {0}", _name);
        }
        public string getClassName() 
        {
            return "Eanlish";
        }
    }
}

上面代码中实现对委托的调用

最后将被调用的委托输出

3.委托的实现方式

第一种：常规实现

private delegate String getAString( string parament);

static void Main(String []args)

{

int temp = 40;

getAString stringMethod = new getAString(temp.ToString); //传递temp.ToString调用委托<br>

Console.WriteLine("String is {0}", stringMethod()); //stringMethod()调用已经接受参数的委托

Console.ReadLine();

}

第二种：多播委托

getAString stringMethod = new getAString(temp.ToString);

stringMethod += temp.ToString;

stringMethod -= temp.ToString;

　　这种调用之后，按照接受参数的次数，委托会生成一个列表，每用+=调用一次，会增加一个列表项，-=调用一次，会移除一个列表项。

第三种：委托数组

当我们定义委托让委托形成一个数组的时候，我们可以通过遍历数组的方式来调用它

delegate double Operations(double x);

    class Program
    {
        static void Main()
        {
            Operations[] operations =
            {
               MathOperations.MultiplyByTwo,
               MathOperations.Square
            };

            for (int i = 0; i < operations.Length; i++)
            {
                Console.WriteLine("Using operations[{0}]:", i);
                DisplayNumber(operations[i], 2.0);
                DisplayNumber(operations[i], 7.94);
                Console.ReadLine();
            }
        }

        static void DisplayNumber(Operations action, double value)
        {
            double result = action(value);
            Console.WriteLine(
               "Input Value is {0}, result of operation is {1}", value, result);
        }
    }

    struct MathOperations
    {
        public static double MultiplyByTwo(double value)
        {
            return value * 2;
        }

        public static double Square(double value)
        {
            return value * value;
        }
    }

上面实例中

将委托定义好

之后就可以遍历它

委托的实现方式还有三种持续更新中！

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