代码，内含说明（界面是两个文本框textbox1，textbox2，和一个button1，界面的Load事件，button的click事件）

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;

namespace Test

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

//CustomClass cc = new CustomClass(1, "Lee");//测试属性值不变化的情况

CustomClass cc = new CustomClass();//空构造函数，一边测试属性值改变

private void Form1_Load(object sender, EventArgs e)

{

cc.Changed += new CustomClass.ChangedEventHandler(cc_Changed);//加载事件

}

private void button1_Click(object sender, EventArgs e)

{

cc.Cid = 1;

cc.Cname = "Lee";//给CustomClass的属性赋值，赋值是引发事件

string str = cc.Cid.ToString() + cc.Cname;

MessageBox.Show(str);

}

private void cc_Changed()//事件

{

textBox1.Text = cc.Cid.ToString();

textBox2.Text = cc.Cname;

}

}

public class CustomClass

{

public delegate void ChangedEventHandler();//定义委托

public event ChangedEventHandler Changed;//定义事件

private int _Cid;

private string _Cname;

public CustomClass()

{

}

public CustomClass(int cCid, string cCname)

{

this._Cid = cCid;

this._Cname = cCname;

}

protected virtual void OnChanged()

{

if (Changed!=null)

{

Changed();

}

}

public int Cid

{

get

{

return _Cid;

}

set

{

if (_Cid!=value)//这里是文本改变时的处理

{

_Cid = value;

OnChanged();//启动事件

}

}

}

public string Cname

{

get

{

return _Cname;

}

set

{

if (_Cname != value)

{

_Cname = value;

OnChanged();

}

}

}

}

}

以下是网上的一段非常经典的属性值改变引发自定义事件的例子，如下;

public class MyClass

{

public event EventHandler MyPropertyChanging;

public event EventHandler MyPropertyChanged;

private int _myProperty;

public int MyProperty

{

get { return _myProperty; }

set

{

if (value != _myProperty)

{

PropertyChagedEventArgs e = new PropertyChagedEventArgs("MyProperty", _myProperty, value);//初始化

if (this.MyPropertyChanging != null)

{

this.MyPropertyChanging(this, e);

if (e.Cancel) return;

}

_myProperty = (int)e.NewValue;

if (this.MyPropertyChanged != null)

{

this.MyPropertyChanged(this, e);

}

}

}

}

}

///

/// 通用的类

///

public class PropertyChagedEventArgs : EventArgs

{

public PropertyChagedEventArgs(string propertyName,object oldValue,object newValue)

{

PropertyName = propertyName;

OldValue = oldValue;

NewValue = newValue;

}

public bool Cancel { get; set; }

public string PropertyName { get; private set; }

public object OldValue { get; private set; }

public object NewValue { get; set; }

}

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