委托、 Lambda表达式和事件——委托

1. 简单示例

    /*
     * 由SharpDevelop创建。
     * 用户： David Huang
     * 日期: 2015/7/27
     * 时间: 10:22
     */
    using System;
   
    namespace Delegate_Book
    {
        class Program
        {
            delegate string GetAString();
   
            struct Currency
            {
                public uint Dollars;
                public ushort Cents;
   
                public Currency(uint Dollars,ushort Cents)
                {
                    this.Dollars=Dollars;
                    this.Cents=Cents;
                }
   
                public override string ToString()
                {
                    return string.Format("${0}.{1,2:00}",Dollars,Cents);
                } 
   
                public static string GetCurrencyUnit()
                {
                    return "Dollar";
                }
            }
   
            public static void Main(string[] args)
            {
                const int x = ;
                //GetAString getAString =new GetAString(x.ToString);
                GetAString getAString=x.ToString;
                Console.WriteLine(getAString());     
   
                Currency currency=new Currency(,);
                getAString=currency.ToString;
                Console.WriteLine(getAString());
   
                Console.WriteLine(new GetAString(new Currency(,).ToString)());
   
                getAString=Currency.GetCurrencyUnit;
                Console.WriteLine(getAString());
   
                Console.Write("Press any key to continue . . . ");
                Console.ReadKey(true);
            }
        }
    }

2. Action<T>和Func<T>委 托

    /*
     * 由SharpDevelop创建。
     * 用户： David Huang
     * 日期: 2015/7/28
     * 时间: 14:31
     */
    using System;
   
    namespace MathOperations
    {
        static class MathOperations
        {
            public static double MutiplyByTwo(double value)
            {
                return *value;
            }
   
            public static double Square(double value)
            {
                return value*value;
            }
        }
   
        delegate double DoubleOp(double x);
   
        class Program
        {
   
            public static void Main(string[] args)
            {
                DoubleOp[] doubleOps={
                    MathOperations.MutiplyByTwo,
                    MathOperations.Square
                };
   
                foreach (var op in doubleOps) {
                    DoTheMath(op,2.5);
                    DoTheMath(op,3.5);
                }
   
                Func<double,double>[] doubleFuncs={
                    MathOperations.MutiplyByTwo,
                    MathOperations.Square
                };
   
                foreach (var func in doubleFuncs) {
                    DoTheFunc(func,2.5);
                    DoTheFunc(func,3.5);
                }
   
                Console.Write("Press any key to continue . . . ");
                Console.ReadKey(true);
            }
   
            static void DoTheMath(DoubleOp operation,double value)
            {
                double result=operation(value);
                Console.WriteLine(string.Format("vlaue is {0},result is {1}",value,result));
            }
   
            static void DoTheFunc(Func<double,double> func,double value)
            {
                var result = func(value);
                Console.WriteLine(string.Format("value is {0},result is {1}",value,result));
            }
   
        }
    }

3. 冒泡排序示例

    /*
     * 由SharpDevelop创建。
     * 用户： David Huang
     * 日期: 2015/7/29
     * 时间: 15:34
     */
    using System;
    using System.Linq;
    using System.Collections.Generic;
   
    namespace BubbleSorter
    {
        class Program
        {
            public static void Main(string[] args)
            {
                //int
                List<int> array=new List<int> {,,,,};
                Sort(array);
                Console.WriteLine(array.ConvertAll(i=>i.ToString()).Aggregate((current,next)=>string.Format("{0},{1}",current,next)).TrimEnd(','));
   
                //泛型
                List<int> list=new List<int> {,,,,};
                Sort(list,IsBiggerThan);
                Console.WriteLine(array.ConvertAll(i=>i.ToString()).Aggregate((current,next)=>string.Format("{0},{1}",current,next)).TrimEnd(','));
   
                //泛型
                List<Person> personList=new List<Person>{
                    new Person{Name="Tom",Age=},
                    new Person{Name="Jack",Age=},
                    new Person{Name="Penny",Age=},
                    new Person{Name="Lucy",Age=}
                };
                Sort(personList,IsOlderThan);
                foreach (Person person in personList) {
                    Console.WriteLine(person);
                }
   
                Console.Write("Press any key to continue . . . ");
                Console.ReadKey(true);
            }
   
            static bool IsOlderThan(Person p1,Person p2)
            {
                return p1.Age>p2.Age;
            }
   
            static bool IsBiggerThan(int a,int b)
            {
                return a>b;
            }
   
            static void Sort(IList<int> sortArray)
            {
                bool swapped=true;
   
                do
                {
                    swapped=false;
   
                    for (int i = ; i < sortArray.Count-; i++) {
                        if (sortArray[i]>sortArray[i+]) {
                            int tmp=sortArray[i];
                            sortArray[i]=sortArray[i+];
                            sortArray[i+]=tmp;
                            swapped=true;
                        }
                    }
   
                }while (swapped);
            }
   
            static void Sort<T>(IList<T> list,Func<T,T,bool> comparison)
            {
                bool swapped=true;
   
                do{
                    swapped=false;
   
                    for (int i = ; i < list.Count-; i++) {
                        if (comparison(list[i],list[i+])) {
                            T temp=list[i];
                            list[i]=list[i+];
                            list[i+]=temp;
                            swapped=true;
                        }
                    }
   
                }while(swapped);
            }
        }
   
        class Person
        {
            public string Name{get;set;}
            public int Age{get;set;}
   
            public override string ToString()
            {
                return string.Format("Name:{0},Age:{1}",Name,Age);
            }
        }
    }

4. 多播委托

    /*
     * 由SharpDevelop创建。
     * 用户： David Huang
     * 日期: 2015/7/30
     * 时间: 14:37
     */
    using System;
   
    namespace 多播
    {
        public static class MathOperations
        {
            public static void MutiplyByTwo(double value)
            {
                Console.WriteLine(string.Format("method: MutiplyByTwo, value: {0}, result: {1}",value,*value));
            }
   
            public static void Square(double value)
            {
                Console.WriteLine(string.Format("method: Square, value: {0}, result: {1}",value,value*value));
            }
        }
   
        class Program
        {
            public static void Main(string[] args)
            {
                Action<double> mathOperations=MathOperations.MutiplyByTwo;
                mathOperations+=MathOperations.Square;
   
                DoTheMath(mathOperations,2.5);
                DoTheMath(mathOperations,3.5);
   
                Console.Write("Press any key to continue . . . ");
                Console.ReadKey(true);
            }
   
            static void DoTheMath(Action<double> action,double value)
            {
                action(value);
            }
        }
    }

5. 匿名委托

    /*
     * 由SharpDevelop创建。
     * 用户： David Huang
     * 日期: 2015/7/30
     * 时间: 16:19
     */
    using System;
   
    namespace 匿名
    {
        class Program
        {
            public static void Main(string[] args)
            {
                Func<int,int> anonDel=delegate(int i)
                {
                    return i*;
                };
   
                Console.WriteLine(anonDel());
                // TODO: Implement Functionality Here
   
                Console.Write("Press any key to continue . . . ");
                Console.ReadKey(true);
            }
        }
    }