c# 事件示例

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
using System.IO;

/// <summary>
/// 自定义缩略图控件
/// </summary>
public  class ctlPictureBox
{
    public delegate void PicClickHandler(object sender, PictureArgs e);
    /// <summary>
    /// 定义单击事件
    /// </summary>
    public event PicClickHandler PicClick;

    protected virtual void OnPictureClick(PictureArgs e)
    {//事件触发方法
        if (PicClick != null)
        {//判断事件是否为空
            PicClick(this, e);//触发事件
        }
    }
  //激发事件
    private void pbImg_Click(object sender, EventArgs e)
    {
        PictureArgs args = new PictureArgs();
        args.FileName = fileName;
        OnPictureClick(args);
    }

}

   
public class PictureArgs : EventArgs
{
    private string filename = "";
    /// <summary>
    /// 文件名称
    /// </summary>
    public string FileName
    {
        get { return filename; }
        set { filename = value; }
    }
}

   

示例2

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace test
{
 public partial class MyControl: UserControl
 {
  public MyControl()
  {
   InitializeComponent();
  }

        public delegate int MyDelegate(string str);

        public MyDelegate ClickHandler = null;

        private void button1_Click(object sender, EventArgs e)
        {
            if (ClickHandler != null)
            {
                ClickHandler("hello");
            }
        }
 }
}

调用方法

public int Test(string str)
        {
            MessageBox.Show(str);
            return 1;
        }

        public int Test1(string str)
        {
            MessageBox.Show(str +"," + str);
            return 1;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            myControl1.ClickHandler += Test;
            myControl1.ClickHandler += Test1;
         
          //  myControl1.ClickHandler -= Test1;
        }