Add New Row When Focus On Last Column

    private DataGridViewRowCollection collection;
        private DataTable dt;// this is bound to DataGridView
        private void dataGridView1_CellEnter(object sender, DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex == dataGridView1.ColumnCount - 1)
            {
                DataRow dr = dt.NewRow();
                dt.Rows.Add(dr);
                lblRows.Text = dataGridView1.Rows.Count.ToString();
            }
        }