ArrayList

50         void TaoBangRandomCauHoi(DataTable BangQuestion)
51         {
52
53             try
54             {
55                 Random Rnd = new Random();
56                 ArrayList ArrQuestion = new ArrayList();
57
58                 ArrQuestion.Clear();
59                 int x, dem = 0;
60                 int SoCauTrongBangGoc = BangQuestion.Rows.Count;
61                 while (dem < SoCauNgauNhien)
62                 {
63                     x = Rnd.Next(0, SoCauTrongBangGoc);
64                     if (!ArrQuestion.Contains(x))
65                     {
66                         ArrQuestion.Add(x);
67                         dem++;
68                     }
69                 }
70                 for (int j = SoCauTrongBangGoc - 1; j >= 0; j--)
71                     if (!ArrQuestion.Contains(j))
72                         BangQuestion.Rows.RemoveAt(j);
73
74                 BangDeThi = BangQuestion;
75                 BangDeThi.Columns.Add("cauhoi,DAPAN");
76
77             }
78             catch (Exception ex)
79             { MessageBox.Show(ex.Message); }
80
81         }

82         void TaoBangRandomCauTraLoi()
83         {
84             try
85             {
86                 SoCauHoi = BangDeThi.Rows.Count;
87                 string DapAnDung = "";
88                 string A, B, C, D;
89                 int DapAn;
90                 Random Rnd = new Random();
91                 ArrayList ArrDapAn = new ArrayList();
92                 for (int i = 0; i < SoCauHoi; i++)
93                 {
94                     A = "";
95                     B = "";
96                     C = "";
97                     D = "";
98                     DapAnDung = "";
99                     DapAn = 0;
100                     ArrDapAn.Clear();
101                     ArrDapAn.Add(2);
102                     ArrDapAn.Add(3);
103                     ArrDapAn.Add(4);
104                     ArrDapAn.Add(5);
105
106                     DapAn = Rnd.Next(ArrDapAn.Count);
107                     A = BangDeThi.Rows[i][(int)ArrDapAn[DapAn]].ToString();
108                     if ((BangDeThi.Rows[i][6].ToString().ToUpper().Contains("A") && (int)ArrDapAn[DapAn] == 2) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("B") && (int)ArrDapAn[DapAn] == 3) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("C") && (int)ArrDapAn[DapAn] == 4) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("D") && (int)ArrDapAn[DapAn] == 5))
109                         DapAnDung += "A";
110                     ArrDapAn.RemoveAt(DapAn);
111                     DapAn = Rnd.Next(ArrDapAn.Count);
112                     B = BangDeThi.Rows[i][(int)ArrDapAn[DapAn]].ToString();
113                     if ((BangDeThi.Rows[i][6].ToString().ToUpper().Contains("A") && (int)ArrDapAn[DapAn] == 2) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("B") && (int)ArrDapAn[DapAn] == 3) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("C") && (int)ArrDapAn[DapAn] == 4) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("D") && (int)ArrDapAn[DapAn] == 5))
114                         DapAnDung += "B";
115                     ArrDapAn.RemoveAt(DapAn);
116                     DapAn = Rnd.Next(ArrDapAn.Count);
117                     C = BangDeThi.Rows[i][(int)ArrDapAn[DapAn]].ToString();
118                     if ((BangDeThi.Rows[i][6].ToString().ToUpper().Contains("A") && (int)ArrDapAn[DapAn] == 2) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("B") && (int)ArrDapAn[DapAn] == 3) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("C") && (int)ArrDapAn[DapAn] == 4) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("D") && (int)ArrDapAn[DapAn] == 5))
119                         DapAnDung += "C";
120                     ArrDapAn.RemoveAt(DapAn);
121                     DapAn = Rnd.Next(ArrDapAn.Count);
122                     D = BangDeThi.Rows[i][(int)ArrDapAn[DapAn]].ToString();
123                     if ((BangDeThi.Rows[i][6].ToString().ToUpper().Contains("A") && (int)ArrDapAn[DapAn] == 2) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("B") && (int)ArrDapAn[DapAn] == 3) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("C") && (int)ArrDapAn[DapAn] == 4) || (BangDeThi.Rows[i][6].ToString().ToUpper().Contains("D") && (int)ArrDapAn[DapAn] == 5))
124                         DapAnDung += "D";
125                     BangDeThi.Rows[i][2] = A;
126                     BangDeThi.Rows[i][3] = B;
127                     BangDeThi.Rows[i][4] = C;
128                     BangDeThi.Rows[i][5] = D;
129                     BangDeThi.Rows[i][6] = DapAnDung;
130                 }
131             }
132             catch (Exception ex)
133             { MessageBox.Show(ex.Message); }
134         }