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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        CheckBox[] checkBoxs;
        private void Form1_Load(object sender, EventArgs e)
        {
            checkBoxs = new CheckBox[]
            {
                checkBox1,checkBox2,checkBox3,checkBox4,checkBox5,
            };
            for (int i = 0; i < checkBoxs.Length; i++)
            {
                checkBoxs[i].CheckedChanged += new EventHandler(checkBoxs_CheckedChanged);
                checkBoxs[i].Tag = i + 1;
            }
        }

        void checkBoxs_CheckedChanged(object sender, EventArgs e)
        {
            var ckbk = (CheckBox)sender;
            int Number = (int)ckbk.Tag;
            this.Text = Number.ToString();
        }
    }
}