private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {
            this.BindingContext[(DataTable)dataGridView1.DataSource].EndCurrentEdit();
            DataTable dt = ((DataTable)dataGridView1.DataSource).GetChanges();
            if (dt != null)
            {
                main_da.Update((DataTable)dataGridView1.DataSource);
                /*((DataTable)dataGridView1.DataSource).Clear();
                main_da.Fill((DataTable)dataGridView1.DataSource);*/
                ((DataTable)dataGridView1.DataSource).AcceptChanges();
            }
        }

main_da = new SqlDataAdapter("select id,* from " + rdt.Rows[0]["ref_table"].ToString(), Properties.Settings.Default.masterConnectionString);
SqlCommandBuilder cb = new SqlCommandBuilder(main_da);
main_da.InsertCommand = cb.GetInsertCommand();
main_da.DeleteCommand = cb.GetDeleteCommand();
main_da.UpdateCommand = cb.GetUpdateCommand();