C# INotifyPropertyChanged用法，监听属性值发生改变

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有时候，我们需要监听属性值的变化，当属性值发生改变时，需要被通知，没有改变时不需要通知，这个时候可以用INotifyPropertyChanged来做，也可以自定义委托事件，也可以实现，方法多多，在这里只介绍INotifyPropertyChanged的方法，目的是当属性值发生变化时，才出发事件

案例: 创建一个父类Person，继承INotifyPropertyChanged类，然后让Man类去继承

Person类：

using System;using System.Collections.Generic;using System.Text;using System.ComponentModel;namespace Demo{    public delegate void ChangedHandler(object sender, object v);    public class Person : INotifyPropertyChanged    {        #region INotifyPropertyChanged 成员        public event PropertyChangedEventHandler PropertyChanged;        public virtual void OnPropertyChanged(string propertyName)        {            PropertyChangedEventHandler hander = PropertyChanged;            if (hander != null)                hander(this, new PropertyChangedEventArgs(propertyName));        }        #endregion        /// <summary>        /// 属性变换事件        /// </summary>        /// <param name="sender">源</param>        /// <param name="v">变化后的值</param>        /// <param name="old">变化前的值</param>        /// <param name="hander"></param>        protected virtual void OnChanged(object sender, object v, object old, ChangedHandler hander)        {            if (!v.Equals(old) && hander != null)                hander(sender, v);        }    }}

Man类

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace Demo{    public class Man:Person    {          public event ChangedHandler ChangeName;        public event ChangedHandler ChangeAge;       string name = string.Empty;        public virtual string Name        {            get { return name; }            set            {                base.OnChanged(this, value, Name, ChangeName);                name = value;                OnPropertyChanged("Name");            }        }        int age = 10;        public virtual int Age        {            get { return age; }            set            {                base.OnChanged(this, value, Age, ChangeAge);                age = value;                OnPropertyChanged("Age");            }        }    }}

Form1 界面

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System;using System.Collections.Generic;using System.Text;using System.ComponentModel;namespace Demo{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        Man m = new Man();        private void Form1_Load(object sender, EventArgs e)        {            m = new Man();               m.ChangeName += new ChangedHandler(m_ChangeName);            m.ChangeAge += new ChangedHandler(m_ChangeAge);        }        void m_ChangeAge(object sender, object v)        {            SetText("m.Age " + v.ToString());        }        void m_ChangeName(object sender, object v)        {            SetText("m.Name " + v.ToString());        }        private void btnName_Click(object sender, System.EventArgs e)        {            m.Name = textBox2.Text;        }        public void SetText(string txt)        {            textBox1.Text += txt+ "\r\n";        }        private void btnAge_Click(object sender, System.EventArgs e)        {            m.Age = int.Parse(textBox3.Text);        }    }}

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