“System.ArgumentNullException”类型的第一次机会异常在 mscorlib.dll 中发生 其他信息: 值不能为 null
这个问题该怎么解决呢
1 #region//向PFXJ表中插入Ln项集，并返回Ln,参数为Ln的后选项(Cn)
2 public string[,] LnInsertToPFXJ(string[,] L, int minSupport)
3 {
4 int hang = L.GetLength(0);
5 int lie = L.GetLength(1);
6
7 string[,] Cn = new string[hang, lie];
8 int max = 0;//得到的Ln的实际行数
9
10 for (int i = 0; i < hang; i++)
11 {
12 StreamReader sr = new StreamReader("My.txt", Encoding.GetEncoding("gb2312"));
13 string line = string.Empty;
14 int zhiChiPinDu = 0;
15 int num = 0;//用来判断是否二维数组的行中元素满足条件
16 string strLn = string.Empty;//存候选项集元素
17 while ((line = sr.ReadLine()) != null)
18 {
19 for(
20
21 int j = 0; j < lie; j++)
22 {
23 if (line.Contains(L[i, j]))/*此处抛出异常，对应堆栈中的中的> HouseSale.exe!HouseSale.Apriori.LnInsertToPFXJ(string[,] L, int minSupport) 行 294 C#*/
24 {
25 int lineLen = line.Length;
26 if (L[i, j].Length == 3 && lineLen > 3 && (line.Substring(lineLen - 4, 1) == "I"))
27 {
28 int len = line.IndexOf(L[i, j]);
29 string str = line.Substring(len + 3, 1);
30 if (str == "I")
31 {
32 num += 1;
33 }
34 }
35 else
36 {
37 num += 1;
38 }
39 }
40 }
41 if (num == lie)
42 {
43 zhiChiPinDu += 1;
44 }
45 num = 0;
46 }
47 sr.Close();
48 if (zhiChiPinDu >= minSupport)
49 {
50 for (int j = 0; j < lie; j++)
51 {
52 strLn += (L[i, j] + ",");
53
54 }
55 strLn = strLn.Substring(0, strLn.Length - 1);
56 string sql = "insert into PFXJ values('" + lie.ToString() + "','" + strLn + "','" + zhiChiPinDu.ToString() + "')";
57 ErpApplication erp = new ErpApplication();
58
59 erp.Esql(sql);
60
61
62 max += 1;
63
64 string myStr = string.Empty;
65 for (int j = 0; j < lie; j++)
66 {
67 if (strLn.Contains(","))
68 {
69 int dLen = strLn.IndexOf(",");
70 myStr = strLn.Substring(0, dLen);
71
72 Cn[max - 1, j] = myStr;
73 strLn = strLn.Substring(dLen + 1, strLn.Length - dLen - 1);
74 }
75 else
76 {
77 Cn[max - 1, j] = strLn;
78 }
79 }
80 }
81
82 strLn = string.Empty;
83 }
调用堆栈如下：
[外部代码]
> HouseSale.exe!HouseSale.Apriori.LnInsertToPFXJ(string[,] L, int minSupport) 行 294 C#
HouseSale.exe!HouseSale.Apriori.MyApriori(string[] Id, int minSupport) 行 169 C#
HouseSale.exe!HouseSale.DigDataForm.button5_Click(object sender, System.EventArgs e) 行 97 C#
[外部代码]
HouseSale.exe!HouseSale.ChooseForm.button5_Click(object sender, System.EventArgs e) 行 205 C#
[外部代码]
HouseSale.exe!HouseSale.Program.Main() 行 21 C#
[外部代码]
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