1、从网上找了个中缀算法(也不知道什么前缀后缀，抱歉),可以对字符串表达式进行运算
2、有些时候还是会用到ASCII码表的
char c = expression[k];//expression为一字符串
int intAsciiCode = (int)c;
3、里面用到了解决多种字符串日期显示格式，转换为日期类型的办法
DateTime time = DateTime.Now;
DateTimeFormatInfo dtfi = new CultureInfo("zh-CN", true).DateTimeFormat;
DateTime.TryParseExact(strTime, new string[] { "yyyyMMdd", "yyyy.M.d", "d-M-yyyy", "d-M月-yyyy", "yyyy-M-d", "yyyy_M_d" }, dtfi, DateTimeStyles.None, out time);//strTime为字符串类型日期
1 public class DataTableCompute
2 {
3 /// <summary>
4 /// 对DataTabella行上的列根据运算式计算
5 /// </summary>
6 /// <param name="dicDecimal">数值类型表达式键值对</param>
7 /// <param name="dicTime">时间类型表达式键值对</param>
8 /// <param name="row">DataTable表上的行</param>
9 public static void ComputeColumns(Dictionary<string, string> dicDecimal, Dictionary<string, string> dicTime, DataRow row)
10 {
11 if (dicDecimal != null && dicDecimal.Count > 0)
12 {
13 foreach (KeyValuePair<string, string> kvp in dicDecimal)
14 {
15 GetExpressionByType(row, kvp, "decimal");
16 }
17 }
18 if (dicTime != null && dicTime.Count > 0)
19 {
20 foreach (KeyValuePair<string, string> kvp in dicTime)
21 {
22 GetExpressionByType(row, kvp, "time");
23 }
24 }
25
26 }
27
28 private static void GetExpressionByType(DataRow row, KeyValuePair<string, string> kvp, string type)
29 {
30 string result = kvp.Key;
31 string expression = kvp.Value;
32 string[] cols = expression.Split(new char[] { ‘(‘, ‘)‘, ‘+‘, ‘-‘, ‘*‘, ‘/‘, ‘\\‘ },StringSplitOptions.RemoveEmptyEntries);
33 for (int m = 0; m < cols.Length; m++)
34 {
35 if (type == "time")
36 {
37 DateTime time = DateTime.Now;
38 if (cols[m].ToLower() != "now")
39 {
40 DateTimeFormatInfo dtfi = new CultureInfo("zh-CN", true).DateTimeFormat;
41 if (!DateTime.TryParseExact(row[cols[m]].ToString(), new string[] { "yyyyMMdd", "yyyy.M.d", "d-M-yyyy", "d-M月-yyyy", "yyyy-M-d", "yyyy_M_d" }, dtfi, DateTimeStyles.None, out time))
42 {
43 time = DateTime.Now;
44 }
45 }
46 cols[m] = (time.Year * 12 + time.Month).ToString();
47 }
48 else
49 {
50 double d = 0;
51 if (double.TryParse(row[cols[m]].ToString(), out d))
52 {
53 d = Math.Round(d, 3);
54 }
55 cols[m] = d.ToString();
56 }
57 }
58 StringBuilder newExpression = new StringBuilder();
59 int n = 0;
60 for (int k = 0; k < expression.Length; k++)
61 {
62 char c = expression[k];
63 int intAsciiCode = (int)c;
64 if (intAsciiCode >= 40 && intAsciiCode <= 47)
65 {
66 newExpression.Append(c.ToString() + " ");
67 continue;
68 }
69 if (c == ‘F‘ || c == ‘n‘)
70 {
71 newExpression.Append(cols[n] + " ");
72 n++;
73 }
74 }
75 string str = newExpression.ToString();
76 row[result] = CalculateResult(str);
77 }
78 private static double CalculateResult(string expre)
79 {
80 List<string> temp = getColuExpression(expre);
81 try
82 {
83 while (temp.Count > 1)
84 {
85 for (int i = 0; i < temp.Count; i++)
86 {
87 double resultTemp = 0;
88 if (temp[i] == "+")
89 resultTemp = Convert.ToDouble(temp[i - 2]) + Convert.ToDouble(temp[i - 1]);
90 else if (temp[i] == "-")
91 resultTemp = Convert.ToDouble(temp[i - 2]) - Convert.ToDouble(temp[i - 1]);
92 else if (temp[i] == "*")
93 resultTemp = Convert.ToDouble(temp[i - 2]) * Convert.ToDouble(temp[i - 1]);
94 else if (temp[i] == "/")
95 resultTemp = Convert.ToDouble(temp[i - 2]) / Convert.ToDouble(temp[i - 1]);
96 else
97 continue;
98 temp[i - 2] = resultTemp.ToString();
99 temp.RemoveAt(i);
100 temp.RemoveAt(i - 1);
101 break;
102 }
103 }
104 }
105 catch (Exception ex)//计算表达式的值错误，导致无法运算
106 {
107 temp.Clear();
108 temp.Add("0");
109 }
110 return Convert.ToDouble(temp[0]);
111 }
112 private static List<string> getColuExpression(string exp)
113 {
114 System.Text.ASCIIEncoding asc = new System.Text.ASCIIEncoding();
115 Stack st = new Stack();
116 string[] temp = exp.Split(new char[] { ‘ ‘ }, StringSplitOptions.RemoveEmptyEntries);
117 List<string> value = new List<string>();
118
119 for (int i = 0; i < temp.Length; i++)
120 {
121 int num = (int)asc.GetBytes(temp[i])[0];
122 if (num < 48 && num > 39)
123 {
124 if (st.Count > 0)
125 {
126 string operatorStr = st.Peek().ToString();
127 if (temp[i] == "*" || temp[i] == "/")
128 {
129 if (temp[i + 1] == "(")
130 {
131 st.Push(temp[i]);
132
133 continue;
134 }
135 else
136 {
137 if (operatorStr == "(")
138 {
139 st.Push(temp[i]);
140 continue;
141 }
142 else if (operatorStr == "*" || operatorStr == "/")
143 {
144 value.Add(st.Pop().ToString());
145 st.Push(temp[i]);
146 continue;
147 }
148 else
149 {
150 st.Push(temp[i]);
151 continue;
152 }
153 }
154 }
155 else if (temp[i] == "+" || temp[i] == "-")
156 {
157 if (operatorStr == "(")
158 {
159 st.Push(temp[i]);
160 continue;
161 }
162 else
163 {
164 value.Add(st.Pop().ToString());
165 if (st.Count > 0 && st.Peek().ToString() != "(")
166 {
167 value.Add(st.Pop().ToString());
168 }
169 st.Push(temp[i]);
170 continue;
171 }
172 }
173 else if (temp[i] == "(")
174 {
175 st.Push(temp[i]);
176 continue;
177 }
178 else
179 {
180 if (i + 1 == temp.Length)
181 {
182 value.Add(st.Pop().ToString());
183 st.Pop();
184 while (st.Count > 0)
185 value.Add(st.Pop().ToString());
186 break;
187 }
188 else
189 {
190 value.Add(st.Pop().ToString());
191 st.Pop();
192 continue;
193 }
194 }
195 }
196 else
197 {
198 st.Push(temp[i]);
199 continue;
200 }
201 }
202 else if (i + 1 == temp.Length)
203 {
204 value.Add(temp[i]);
205 value.Add(st.Pop().ToString());
206 while (st.Count > 0)
207 value.Add(st.Pop().ToString());
208 break;
209 }
210 else
211 {
212 value.Add(temp[i]);
213 continue;
214 }
215 }
216 return value;
217 }
218 }
DataTable列计算类
时间： 2024-10-20 17:09:18