//dangnhap
public static string KiemTraDangNhap(string tk, string mk)
{
if (tk == "" || mk == "")
{
string a = "";
return(a);
}
return(DL_DangNhap.DangNhap(tk, mk));
}
//kiem tra doi mat khau
public static bool DoiMatKhau(string tk, string mk)
{
return(DL_DangNhap.MatKhauMoi(tk, mk));
}