DataTable列上多值运算

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

  public class DataTableCompute
     {
         /// <summary>
         /// 对DataTabella行上的列根据运算式计算
         /// </summary>
         /// <param name="dicDecimal">数值类型表达式键值对</param>
         /// <param name="dicTime">时间类型表达式键值对</param>
         /// <param name="row">DataTable表上的行</param>
         public static void ComputeColumns(Dictionary<string, string> dicDecimal, Dictionary<string, string> dicTime, DataRow row)
         {
             if (dicDecimal != null && dicDecimal.Count > )
             {
                 foreach (KeyValuePair<string, string> kvp in dicDecimal)
                 {
                     GetExpressionByType(row, kvp, "decimal");
                 }
             }
             if (dicTime != null && dicTime.Count > )
             {
                 foreach (KeyValuePair<string, string> kvp in dicTime)
                 {
                     GetExpressionByType(row, kvp, "time");
                 }
             }

         }

         private static void GetExpressionByType(DataRow row, KeyValuePair<string, string> kvp, string type)
         {
             string result = kvp.Key;
             string expression = kvp.Value;
             string[] cols = expression.Split(new char[] { '(', ')', '+', '-', '*', '/', '\\' },StringSplitOptions.RemoveEmptyEntries);
             for (int m = ; m < cols.Length; m++)
             {
                 if (type == "time")
                 {
                     DateTime time = DateTime.Now;
                     if (cols[m].ToLower() != "now")
                     {
                         DateTimeFormatInfo dtfi = new CultureInfo("zh-CN", true).DateTimeFormat;
                         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))
                         {
                             time = DateTime.Now;
                         }
                     }
                     cols[m] = (time.Year *  + time.Month).ToString();
                 }
                 else
                 {
                     double d = ;
                     if (double.TryParse(row[cols[m]].ToString(), out d))
                     {
                         d = Math.Round(d, );
                     }
                     cols[m] = d.ToString();
                 }
             }
             StringBuilder newExpression = new StringBuilder();
             int n = ;
             for (int k = ; k < expression.Length; k++)
             {
                 char c = expression[k];
                 int intAsciiCode = (int)c;
                 if (intAsciiCode >=  && intAsciiCode <= )
                 {
                     newExpression.Append(c.ToString() + " ");
                     continue;
                 }
                 if (c == 'F' || c == 'n')
                 {
                     newExpression.Append(cols[n] + " ");
                     n++;
                 }
             }
             string str = newExpression.ToString();
             row[result] = CalculateResult(str);
         }
         private static double CalculateResult(string expre)
         {
             List<string> temp = getColuExpression(expre);
             try
             {
                 while (temp.Count > )
                 {
                     for (int i = ; i < temp.Count; i++)
                     {
                         double resultTemp = ;
                         if (temp[i] == "+")
                             resultTemp = Convert.ToDouble(temp[i - ]) + Convert.ToDouble(temp[i - ]);
                         else if (temp[i] == "-")
                             resultTemp = Convert.ToDouble(temp[i - ]) - Convert.ToDouble(temp[i - ]);
                         else if (temp[i] == "*")
                             resultTemp = Convert.ToDouble(temp[i - ]) * Convert.ToDouble(temp[i - ]);
                         else if (temp[i] == "/")
                             resultTemp = Convert.ToDouble(temp[i - ]) / Convert.ToDouble(temp[i - ]);
                         else
                             continue;
                         temp[i - ] = resultTemp.ToString();
                         temp.RemoveAt(i);
                         temp.RemoveAt(i - );
                         break;
                     }
                 }
             }
             catch (Exception ex)//计算表达式的值错误，导致无法运算
             {
                 temp.Clear();
                 temp.Add("");
             }
             return Convert.ToDouble(temp[]);
         }
         private static List<string> getColuExpression(string exp)
         {
             System.Text.ASCIIEncoding asc = new System.Text.ASCIIEncoding();
             Stack st = new Stack();
             string[] temp = exp.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
             List<string> value = new List<string>();

             for (int i = ; i < temp.Length; i++)
             {
                 int num = (int)asc.GetBytes(temp[i])[];
                 if (num <  && num > )
                 {
                     if (st.Count > )
                     {
                         string operatorStr = st.Peek().ToString();
                         if (temp[i] == "*" || temp[i] == "/")
                         {
                             if (temp[i + ] == "(")
                             {
                                 st.Push(temp[i]);

                                 continue;
                             }
                             else
                             {
                                 if (operatorStr == "(")
                                 {
                                     st.Push(temp[i]);
                                     continue;
                                 }
                                 else if (operatorStr == "*" || operatorStr == "/")
                                 {
                                     value.Add(st.Pop().ToString());
                                     st.Push(temp[i]);
                                     continue;
                                 }
                                 else
                                 {
                                     st.Push(temp[i]);
                                     continue;
                                 }
                             }
                         }
                         else if (temp[i] == "+" || temp[i] == "-")
                         {
                             if (operatorStr == "(")
                             {
                                 st.Push(temp[i]);
                                 continue;
                             }
                             else
                             {
                                 value.Add(st.Pop().ToString());
                                 if (st.Count >  && st.Peek().ToString() != "(")
                                 {
                                     value.Add(st.Pop().ToString());
                                 }
                                 st.Push(temp[i]);
                                 continue;
                             }
                         }
                         else if (temp[i] == "(")
                         {
                             st.Push(temp[i]);
                             continue;
                         }
                         else
                         {
                             if (i +  == temp.Length)
                             {
                                 value.Add(st.Pop().ToString());
                                 st.Pop();
                                 while (st.Count > )
                                     value.Add(st.Pop().ToString());
                                 break;
                             }
                             else
                             {
                                 value.Add(st.Pop().ToString());
                                 st.Pop();
                                 continue;
                             }
                         }
                     }
                     else
                     {
                         st.Push(temp[i]);
                         continue;
                     }
                 }
                 else if (i +  == temp.Length)
                 {
                     value.Add(temp[i]);
                     value.Add(st.Pop().ToString());
                     while (st.Count > )
                         value.Add(st.Pop().ToString());
                     break;
                 }
                 else
                 {
                     value.Add(temp[i]);
                     continue;
                 }
             }
             return value;
         }
     }

DataTable列计算类