C#自定义事件之属性改变引发事件示例

本文实例为大家分享了c#属性改变引发事件示例的具体代码，供大家参考，具体内容如下

using system;
using system.collections.generic;
using system.linq;
using system.text;

namespace consoleapplication15
{
 class program
 {
  static void main(string[] args)
  {
   monitor m = new monitor();
   m.propertychanging += new monitor.eventhandler(m_propertychanging);
   m.year = 2014;
   m.year = 1890;
   m.year = 2013;

  }

  static bool first=false;
  static void m_propertychanging(object sender, propertychangingeventargs e)
  {
   if (first==false)
   {
    first = true;
   }
   else
   {
    if (e.newvalue < 1900 || e.newvalue > 3000)
    e.cancel = true;
   }
  }
 }

 //（属性正在改变的时候）事件数据
 class propertychangingeventargs : eventargs
 {
  //构造函数
  public propertychangingeventargs(string propertyname, int oldvalue, int newvalue)
  {
   _propertyname = propertyname;
   _oldvalue = oldvalue;
   _newvalue = newvalue;
  }

  //存储数据
  private string _propertyname;
  private int _oldvalue;
  private int _newvalue;
  private bool _cancel;

  //获取或设置属性
  public string propertyname
  {
   set
   {
    _propertyname = value;
   }
   get
   {
    return _propertyname;
   }
  }
  public int oldvalue
  {
   set
   {
    _oldvalue = value;
   }
   get
   {
    return _oldvalue;
   }
  }
  public int newvalue
  {
   set
   {
    _newvalue = value;
   }
   get
   {
    return _newvalue;
   }
  }
  public bool cancel
  {
   set
   {
    _cancel = value;
   }
   get
   {
    return _cancel;
   }
  }
 }

 class monitor
 {
  //定义委托
  public delegate void eventhandler(object sender, propertychangingeventargs e);
  //定义事件
  public event eventhandler propertychanging;
  
  //事件处理（用属性方法）
  int _yearvalue;
  public int year
  {
   get
   {
    return _yearvalue;
   }
   set
   {
    if (_yearvalue != value)
    {
     if (propertychanging != null)
     {
      propertychangingeventargs e = new propertychangingeventargs("year", _yearvalue, value);
      propertychanging(this, e);
      if (e.cancel)
      {
       return;
      }
      else
      {
       _yearvalue = value;
      }
     }
    }
   }
  }
 }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。