事件

来源：互联网发布：手机显微镜软件编辑：程序博客网时间：2024/04/28 11:12

设计一个可统计单击次数的按钮,它提供一个自定义的MyClick事件

一、使用自定义事件的委托

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Windows.Forms;namespace 事件练习{    /// <summary>    /// 自定义按钮可以实现记录点击的次数    /// </summary>    public  class MyCustomButton:Button    {        /// <summary>        /// 自定义事件的委托        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        public delegate void MyClickDelegate(object sender, MyClickEventArgs e);        /// <summary>        /// 自定义事件        /// </summary>        public event MyClickDelegate MyClick;        int clickCount = 0;        protected   override void OnClick(EventArgs e)        {            clickCount++;            if (MyClick != null)            {                //激发MyClick事件                MyClick(this, new MyClickEventArgs(clickCount));            }        }    }    /// <summary>    /// 定义MyClick事件参数    /// </summary>    public class MyClickEventArgs : EventArgs    {        /// <summary>        /// 点击次数        /// </summary>        public int clickCount = 0;        public MyClickEventArgs(int clickCountValue)        {            this.clickCount = clickCountValue;        }    }}

二、使用泛型事件

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Windows.Forms;namespace 事件练习{    /* 一、泛型委托的定义如下：    [SerializableAttribute]    public delegate void EventHandler<TEventArgs>(    Object sender,    TEventArgse    ) where TEventArgs: EventArgs    */    /*二、使用EventHandler<>的好处是：    1.只需定义好事件参数类(从EventArgs类派生)    2.不再需要定义独立的事件委托.    */    /// <summary>    /// 自定义按钮可以记录点击次数(使用了泛型委托)    /// </summary>    public class MyCustomButtonUseGenericscDelegate:Button    {        /// <summary>        /// 使用泛型事件可以简化自定义事件        /// </summary>        public event EventHandler<MyClickEventArgs> MyClick;        int clickCount = 0;        protected override void OnClick(EventArgs  e)        {            clickCount++;            if (MyClick != null)            {                MyClick(this, new MyClickEventArgs(clickCount));            }        }    }}

三、前台注册事件

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 事件练习{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();            //挂载事件            myCustomButton1.MyClick += new MyCustomButton.MyClickDelegate(myCustomButton1_MyClick);            myCustomButtonUseGenericscDelegate1.MyClick += new EventHandler<MyClickEventArgs>(myCustomButtonUseGenericscDelegate1_MyClick);        }        void myCustomButtonUseGenericscDelegate1_MyClick(object sender, MyClickEventArgs e)        {            MessageBox.Show(string.Format("点击了{0}次按钮.", e.clickCount));        }        void myCustomButton1_MyClick(object sender, MyClickEventArgs e)        {            MessageBox.Show(string.Format("点击了{0}次按钮.", e.clickCount));        }    }}

源代码下载:点击打开链接