delete event not working

Question

        protected void gvMyRecord_RowDeleting(object sender, GridViewDeleteEventArgs e)

        {

            SqlCommand command = new SqlCommand("DELETE FROM customer_record WHERE customer_id='" +                        ResultGridView.DataKeys[e.RowIndex].Values[0].ToString() + "'");

            connection.Open();

            command.ExecuteNonQuery();

            connection.Close

            FillVendorGrid();

        }

 

QUESTION: i an unable to understand this code please give me some guideline i will be very thank full to you