通过 INotifyPropertyChanged 实现观察者模式（转）

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

namespace Demo
{
    class Program
    {
        public static void Main(string[] args)
        {
            // 创建实例
            DemoCustomer demoCustomer = DemoCustomer.CreateNewCustomer();

            // 实现事件触发需要处理的事情
            demoCustomer.PropertyChanged += new PropertyChangedEventHandler(demoCustomer_PropertyChanged);

            // 更新值引发事件
            demoCustomer.PhoneNumber = "100";

            // 等待
            Console.ReadLine();
        }

        static void demoCustomer_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            // 获取被更改的属性名
            Console.WriteLine(e.PropertyName);

            // 获取最新更新的值
            Console.WriteLine(((DemoCustomer)sender).PhoneNumber);
        }
    }

    // 实现 INotifyPropertyChanged 接口进行监听
    public class DemoCustomer : INotifyPropertyChanged
    {
        // 默认的私有属性
        private Guid idValue = Guid.NewGuid();
        private string customerName = String.Empty;
        private string companyNameValue = String.Empty;
        private string phoneNumberValue = String.Empty;

        /// <summary>
        /// 在更改属性时引发的事件。（这个事件将被外露。）
        /// </summary>
        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }

        // 默认的构造
        private DemoCustomer()
        {
            customerName = "no data";
            companyNameValue = "no data";
            phoneNumberValue = "no data";
        }

        // 简单的工厂模式
        public static DemoCustomer CreateNewCustomer()
        {
            return new DemoCustomer();
        }

        public Guid ID
        {
            get
            {
                return this.idValue;
            }
        }

        public string CompanyName
        {
            get
            {
                return this.companyNameValue;
            }
            set
            {
                if (value != this.companyNameValue)
                {
                    this.companyNameValue = value;

                    // 当发生改变时，那么就触发事件，传入触发的属性名
                    NotifyPropertyChanged("CompanyName");
                }
            }
        }

        public string PhoneNumber
        {
            get
            {
                return this.phoneNumberValue;
            }
            set
            {
                if (value != this.phoneNumberValue)
                {
                    this.phoneNumberValue = value;

                    // 当发生改变时，那么就触发事件，传入触发的属性名
                    NotifyPropertyChanged("PhoneNumber");
                }
            }
        }
    }
}

转自：http://www.cnblogs.com/scarbean/archive/2010/11/05/1870056.html