public void loadnxb(int?selected = null)
{
var nxbs = NxbServeic.GetAll();
ViewBag.id_nxb = new SelectList(nxbs, "id", "name", selected);
}
public void loadNxb()
{
cb_nhaxb.DataSource = NxbServeic.GetAll();
cb_nhaxb.ValueMember = "id";
cb_nhaxb.DisplayMember = "name";
}