1.先定义要触发的事件对象
public class MyEventArgs: System.EventArgs
{
   private int newValue;
   public int NewValue
{
  get{return newValue;}set{newValue = value;}
}
}
2、定义事件代理
public delegate void PropertyChangedHandler(object sender,MyEventArgs e);
3、定义类，并在类中定义事件
public class dog
{
   public event PropertyChangedHandler PropertyChanged;
   //定义事件处理方法
   protected virtual void OnPropertyChanged(MyEventArgs e)
   {
      if (PropertyChanged != null)
         PropertyChanged(this,e);
   }
   private int age;
   public int Age
   {
      get{return age;}
      set{ age = value;
         MyEventArgs e = new MyEventArgs();
         e.NewValue = age;
         OnPropertyChanged(e);
      }
    }
}
4、使用实例
public class Test
{
    public static void main()
    {
          Dog aDog = new Dog();
          aDog.PropertyChanged += new PropertyChantedHandler(aDog_AgeChanged);
          aDog.Age = 10;
    }
    private static void aDog_AgeChanged(object sender, MyEventArgs e)
    {
         Console.WriteLine(e.NewValue);
    }
}