Lambda表达式

最近在看Lambda表达式的文章，所以写了个简单的Demo，Mark一下。

Person.cs

using System;

namespace LambdaDemo
{
    /// <summary>
    /// 人
    /// </summary>
    public class Person
    {
        private DateTime birthday;
        /// <summary>
        /// 设置或获取姓名。
        /// </summary>
        public string Name { get; protected set; }
        /// <summary>
        /// 获取生日。
        /// </summary>
        public string Birthday
        {
            get { return this.birthday.ToString("yyyy年M月d日"); }
        }
        /// <summary>
        /// 获取周岁。
        /// </summary>
        public int Age
        {
            get
            {
                int age = DateTime.Today.Year - birthday.Year - 1;
                if (DateTime.Today.Month > birthday.Month || (DateTime.Today.Month == birthday.Month && DateTime.Today.Day > birthday.Day))
                {
                    ++age;
                }
                if (age < 0)//出生当年为0岁。
                {
                    return 0;
                }
                return age;
            }
        }
        /// <summary>
        /// 获取虚岁。
        /// </summary>
        public int AbsAge
        {
            get
            {
                return DateTime.Today.Year - birthday.Year;
            }
        }
        /// <summary>
        /// 实例化一个人类对象。
        /// </summary>
        /// <param name="name">姓名。</param>
        /// <param name="birthday">生日。</param>
        public Person(string name, string birthday)
        {
            this.Name = name;
            this.birthday = DateTime.Parse(birthday);
            if (this.birthday > DateTime.Today)//比当前日期日期晚的一律取当前日期为生日。
            {
                this.birthday = DateTime.Today;
            }
        }
        public override string ToString()
        {
            return string.Format("{0}，{1}生人，周岁{2}岁，虚岁{3}岁。", this.Name, this.Birthday, this.Age, this.AbsAge);
        }
    }
}

Company.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace LambdaDemo
{
    /// <summary>
    /// 公司
    /// </summary>
    public class Company
    {
        private List<Person> employee;
        /// <summary>
        /// 实例化一个公司。
        /// </summary>
        public Company()
        {
            employee = new List<Person>();
        }
        /// <summary>
        /// 添加一个公司员工。
        /// </summary>
        public void Add(Person item)
        {
            employee.Add(item);
        }
        /// <summary>
        /// 添加一批公司员工。
        /// </summary>
        public void AddRange(IEnumerable<Person> collecttion)
        {
            employee.AddRange(collecttion);
        }
        /// <summary>
        /// 查找某人是否该公司员工。
        /// </summary>
        public bool Contains(Person item)
        {
            return employee.Contains(item);
        }
        /// <summary>
        /// 清理所有的员工。
        /// </summary>
        public void Clear()
        {
            employee.Clear();
        }
        /// <summary>
        /// 移除某个员工。
        /// </summary>
        public bool Remove(Person item)
        {
            return employee.Remove(item);
        }
        /// <summary>
        /// 移除所有满足特定条件的员工。
        /// </summary>
        /// <param name="match">特定条件</param>
        public int RemoveAll(Predicate<Person> match)
        {
            return employee.RemoveAll(match);
        }
        /// <summary>
        /// 移除某个索引位置的员工。
        /// </summary>
        /// <param name="index"></param>
        public void RemoveAt(int index)
        {
            employee.RemoveAt(index);
        }
        /// <summary>
        /// 确定是否存在满足特定条件的员工。
        /// </summary>
        /// <param name="match">特定条件</param>
        public bool Exists(Predicate<Person> match)
        {
            return employee.Exists(match);
        }
        /// <summary>
        /// 将容量设为实际元素数目。
        /// </summary>
        public void TrimExcess()
        {
            employee.TrimExcess();
        }
        /// <summary>
        /// 计算员工某项int32值类型的属性的平均值。
        /// </summary>
        /// <param name="selector">指定用作计算的属性</param>
        public int Average(Func<Person,int> selector)
        {
            return (int)employee.Average(selector);
        }
        /// <summary>
        /// 基于谓词筛选值序列。
        /// </summary>
        public IEnumerable<Person> Where(Func<Person, bool> selector)
        {
            return employee.Where(selector);
        }
        /// <summary>
        /// 公司。
        /// </summary>
        /// <param name="index">员工索引位置。</param>
        public Person this[int index]
        {
            get { return employee[index]; }
            set { employee[index] = value; }
        }
    }
}

Program.cs

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

namespace LambdaDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            //int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
            //int numCount = numbers.Count(s => s % 2 == 1);
            //Console.WriteLine("奇数个数："+numCount);

            //Person[] company = { new Person("张三", "1982-5-7"), new Person("李四", "1983-9-15"), new Person("王五", "1979-1-11"), new Person("孙丽", "1984-11-7"), new Person("钱海", "1979-12-3"), new Person("赵兵", "1986-7-2") };
            //int avgAge = (int)company.Average(p => p.Age);
            //Console.WriteLine("公司员工的平均年龄是：" + avgAge);

            Company company = new Company();
            company.AddRange(new Person[] { new Person("张三", "1982-5-7"), new Person("李四", "1983-9-15"), new Person("王五", "1979-1-11"), new Person("孙丽", "1984-11-7"), new Person("钱海", "1979-12-3"), new Person("赵兵", "1986-7-2") });
            int avgAge = company.Average(p => p.Age);

            var personUpAvgAge = company.Where(p => p.Age >= avgAge);
            Console.WriteLine("公司里年龄达到平均年龄的员工有：");
            foreach (var p in personUpAvgAge)
            {
                Console.WriteLine(p.ToString());
            }
            Console.ReadKey();
        }
    }
}

参考文章：http://msdn.microsoft.com/zh-cn/library/bb397687.aspx