C#

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

namespace dgvTester
{
    public partial class Form1 : Form
    {
        private int counter = 0;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            dataGridView1.RowCount = 10;
            dataGridView1.ColumnCount = 10;
            for (int column = 0; column < dataGridView1.ColumnCount; column++)
                dataGridView1.Columns[column].Width = 50;
            dataGridView1.CellPainting += new System.Windows.Forms.DataGridViewCellPaintingEventHandler(this.dataGridView1_CellPainting);
        }

        private void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            counter++;
            label1.Text = counter.ToString();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            counter = 0;
            label1.Text = counter.ToString();
        }
    }
}