string TaoMaLopMoi()
{
LopBLL lopbll = new LopBLL();
string malop = lopbll.GetMaLopMax();
string[] list = malop.Split('L');
malop = "L" + (Int32.Parse(list[1]) + 1);
return(malop);
}
//string tenLop = null;
//string maKhoiLop = null;
//string siSo = null;
public ThemSuaLop()
{
InitializeComponent();
lbTop.Text = "Thêm lớp mới";
LopBLL lopBll = new LopBLL();
string maLopMax = lopBll.GetMaLopMax();
string[] listtemp = maLopMax.Split('L');
string maLop = listtemp[0];
tbMaLop.Text = maLop;
}