private void hienthi()
{
khachhangBLL pbll = new khachhangBLL();
dataGridView1.DataSource = pbll.hienthikhachhang();
}
private void hienthikhachhang()
{
khachhangBLL pbll = new khachhangBLL();
dgkhachhang.DataSource = pbll.hienthikhachhang();
}