private void LamMoiNguyenLieu(bool state = true) { txtMaNguyenLieu.Text = NguyenLieuBUS.LayMaNguyenLieuMoiNhat() + 1 + ""; txtTenNguyenLieu.Text = txtSoLuong.Text = txtDonViTinh.Text = string.Empty; btnThemNguyenLieu.Enabled = state; btnXoaNguyenLieu.Enabled = !state; btnSuaNguyenLieu.Enabled = !state; btnKhoiPhucNguyenLieu.Enabled = !state; }