private void load_grid()
{
gv1.DataSource = pn.getphieunhaptam();
tbmahang.DataSource = sp.LayDanhSach();
tbmahang.DisplayMember = "tenhang";
tbmahang.ValueMember = "mahang";
edit_sp.DataSource = sp.LayDanhSach();
edit_sp.DisplayMember = "tenhang";
edit_sp.ValueMember = "mahang";
}
public void load_database()
{
combodvt.DataSource = CH.LayDanhSach_dvt();
combodvt.DisplayMember = "donvitinh";
combodvt.ValueMember = "id";
luoitenchngoai.DataSource = CH.LayDanhSach();
}