C# 2.0学习之--匿名代理

 

编译与执行：

csc AnonymousDelegates.cs
            AnonymousDelegates

 

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AnonymousDelegates.cs :

//Copyright (C) Microsoft Corporation.  All rights reserved.

using System;
using System.Collections.Generic;
using System.Text;

namespace AnonymousDelegate_Sample
{

    // Define the delegate method.
    delegate decimal CalculateBonus(decimal sales);

    // Define an Employee type.
    class Employee
    {
        public string name;
        public decimal sales;
        public decimal bonus;
        public CalculateBonus calculation_algorithm;
    }

    class Program
    {

        // This class will define two delegates that perform a calculation.
        // The first will be a named method, the second an anonymous delegate.

        // This is the named method.
        // It defines one possible implementation of the Bonus Calculation algorithm.

        static decimal CalculateStandardBonus(decimal sales)
        {
            return sales / 10;
        }

        static void Main(string[] args)
        {

            // A value used in the calculation of the bonus.
            // Note: This local variable will become a "captured outer variable".
            decimal multiplier = 2;

            // This delegate is defined as a named method.
            CalculateBonus standard_bonus = new CalculateBonus(CalculateStandardBonus);

            // This delegate is anonymous - there is no named method.
            // It defines an alternative bonus calculation algorithm.
            CalculateBonus enhanced_bonus = delegate(decimal sales) { return multiplier * sales / 10; };

            // Declare some Employee objects.
            Employee[] staff = new Employee[5];

            // Populate the array of Employees.
            for (int i = 0; i < 5; i++)
                staff[i] = new Employee();

            // Assign initial values to Employees.
            staff[0].name = "Mr Apple";
            staff[0].sales = 100;
            staff[0].calculation_algorithm = standard_bonus;

            staff[1].name = "Ms Banana";
            staff[1].sales = 200;
            staff[1].calculation_algorithm = standard_bonus;

            staff[2].name = "Mr Cherry";
            staff[2].sales = 300;
            staff[2].calculation_algorithm = standard_bonus;

            staff[3].name = "Mr Date";
            staff[3].sales = 100;
            staff[3].calculation_algorithm = enhanced_bonus;

            staff[4].name = "Ms Elderberry";
            staff[4].sales = 250;
            staff[4].calculation_algorithm = enhanced_bonus;

            // Calculate bonus for all Employees
            foreach (Employee person in staff)
                PerformBonusCalculation(person);

            // Display the details of all Employees
            foreach (Employee person in staff)
                DisplayPersonDetails(person);

        }

        public static void PerformBonusCalculation(Employee person)
        {

            // This method uses the delegate stored in the person object
            // to perform the calculation.
            // Note: This method knows about the multiplier local variable, even though
            // that variable is outside the scope of this method.
            // The multipler varaible is a "captured outer variable".
            person.bonus = person.calculation_algorithm(person.sales);
        }

        public static void DisplayPersonDetails(Employee person)
        {
            Console.WriteLine(person.name);
            Console.WriteLine(person.bonus);
            Console.WriteLine("---------------");
        }
    }
}