Copying and Pasting cs Code

In cs, like in almost any computer programming language, reading data from a file can be tricky. You add extra lines of code to tell the computer what to do. Sometimes you can copy and paste these lines from other peoples’ code.

For example, you can follow the pattern in this listing:

         public DataTable ThongKeLop(string MaHK,string MaLop,int loai)
         {
             SqlConnection con = da.GetConnect();
             ChuanBi3Table(MaHK);
             //Truy van cuoi cung
             string sql4;
             switch (loai)
             {
                 case 0:
                     sql4 = "select sv.MaSV,TenSV,TrungBinhCuoiKyHe10 " +
                            " from DTB left join SinhVien sv on DTB.MaSV=sv.MaSV " +
                            " where MaLop='" + MaLop + "' and TrungBinhCuoiKyHe10 >= 9";
                     break;
                 case 1:
                     sql4 = "select sv.MaSV,TenSV,TrungBinhCuoiKyHe10 " +
                            " from DTB left join SinhVien sv on DTB.MaSV=sv.MaSV " +
                            " where MaLop='" + MaLop + "' and TrungBinhCuoiKyHe10 >=8 and TrungBinhCuoiKyHe10 < 9";
                     break;
                 case 2:
                     sql4 = "select sv.MaSV,TenSV,TrungBinhCuoiKyHe10 " +
                            " from DTB left join SinhVien sv on DTB.MaSV=sv.MaSV " +
                            " where MaLop='" + MaLop + "' and TrungBinhCuoiKyHe10 >=6.5 and TrungBinhCuoiKyHe10 < 8";
                     break;
                 case 3:
                     sql4 = "select sv.MaSV,TenSV,TrungBinhCuoiKyHe10 " +
                            " from DTB left join SinhVien sv on DTB.MaSV=sv.MaSV " +
                            " where MaLop='" + MaLop + "' and TrungBinhCuoiKyHe10 >=5 and TrungBinhCuoiKyHe10 < 6.5";
                     break;
                 case 4:
                     sql4 = "select sv.MaSV,TenSV,TrungBinhCuoiKyHe10 " +
                            " from DTB left join SinhVien sv on DTB.MaSV=sv.MaSV " +
                            " where MaLop='" + MaLop + "' and TrungBinhCuoiKyHe10 >=3.5 and TrungBinhCuoiKyHe10 < 5";
                     break;
                 default:
                     sql4 = "select sv.MaSV,TenSV,TrungBinhCuoiKyHe10 " +
                            " from DTB left join SinhVien sv on DTB.MaSV=sv.MaSV " +
                            " where MaLop='" + MaLop + "' and TrungBinhCuoiKyHe10 < 3.5";
                     break;
             }
             DataTable dt4 = da.GetTable(sql4);
             da.ExcuteNonQuery("delete from Loptc where MaSV in ( select MaSV from Loptc )");
             da.ExcuteNonQuery("delete from Lopdiem10 where MaSV in ( select MaSV from Lopdiem10 )");
             da.ExcuteNonQuery("delete from DTB where MaSV in ( select MaSV from DTB )");
             return dt4;
         }