private void Loaddatavaocombo()
{
List <string> soban = new List <string>();
soban = banBUS.LaysoBan();
comboBox1.DataSource = soban;
}
private void loadDataVaoComboBox()
{
List <string> ban = new List <string>();
ban = banBUS.LaysoBan();
comboBox2.DataSource = ban;
List <string> mathungan = new List <string>();
mathungan = nvBUS.Laymanv();
comboBox2.DataSource = mathungan;
}