how to find the location of the last data entered in a 2D array?

private Button[,] CreateButtonArray(int width, int height)
{
    Button[,] buttonArray = new Button[height, width];
    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            buttonArray[i, j] = new Button();
            buttonArray[i, j].Click += new EventHandler(AnyButton_Click);
            buttonArray[i, j].Tag = new Point(j, i);
        }
    }
    return buttonArray;
}

private void AnyButton_Click(object sender, EventArgs e)
{
    Point p = (Point)((sender as Button).Tag);
    this.textBox1.Text = string.Format("You clicked button[{0}, {1}].", p.Y, p.X);
}