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

namespace clicRegion
{
    public partial class Form1 : Form
    {
        Rectangle[] rc;
        Region[] r;
        public Form1()
        {
            InitializeComponent();
            rc = new Rectangle[3];
            r = new Region[rc.Length];
            rc[0] = new Rectangle(20, 20, 20, 20);
            r[0] = new Region(rc[0]);
            rc[1] = new Rectangle(60, 60, 20, 20);
            r[1] = new Region(rc[1]);
            rc[2] = new Rectangle(100, 100, 20, 20);
            r[2] = new Region(rc[2]);
        }
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            for (int i = 0; i < rc.Length; i++)
                e.Graphics.DrawEllipse(new Pen(Color.Red), rc[i]);
        }

        private void Form1_MouseClick(object sender, MouseEventArgs e)
        {
            int v = 0;
            for (int i = 0; i < r.Length; i++)
            {
                if (r[i].IsVisible(e.Location))
                {
                    v = i + 1;
                    break;
                }
            }
            if (v > 0)
                textBox1.Text = string.Format("Click {0}", v);
            else
                textBox1.Clear();
        }
    }
}