private void btnLuu_Click(object sender, EventArgs e)
        {
            provider p = new provider();
            p.id = txtMa.Text;
            p.name = txtTen.Text;
            p.phone = txtSdt.Text;
            p.email = txtEmail.Text;
            p.address = txtDiaChi.Text;

            if (busNhaCungCap.Insert(p))
            {
                DialogResult = DialogResult.OK;
                this.Close();
            }
            else
            {
                DialogResult = DialogResult.Cancel;
                XtraMessageBox.Show("Có lỗi trong quá trình thêm, vui lòng kiểm tra lại", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1);
                this.Close();
            }
        }
 partial void Deleteprovider(provider instance);
 partial void Updateprovider(provider instance);
 partial void Insertprovider(provider instance);
        void gvNhaCungCap_FocusedRowChanged(object sender, DevExpress.XtraGrid.Views.Base.FocusedRowChangedEventArgs e)
        {
            if (gvNhaCungCap.SelectedRowsCount != 1)
                return;

            ncc = (provider)gvNhaCungCap.GetFocusedRow();
            lblTenNhaCungCap.Text = ncc.name;
            lblDiaChi.Text = ncc.address;
            lblSoDienThoai.Text = ncc.phone;
            lblEmail.Text = ncc.email;

            dgvSanPhamCungCap.DataSource = busNhaCungCap.GetProduct(ncc);
        }