1         public static decimal Round(decimal d, decimal unit)
2         {
3             decimal rm = d % unit;
4             decimal result = d - rm;
5             if (rm >= unit / 2)
6                 result += unit;
7             return result;
8         }

1         public static decimal Jinyi(decimal d, decimal unit)
2         {
3             decimal rm = d % unit;
4             decimal result = d - rm;
5             if (rm > 0)
6                 result += unit;
7             return result;
8         }

1         public static decimal Quzheng(decimal d, decimal unit)
2         {
3             decimal rm = d % unit;
4             decimal result = d - rm;
5             return result;
6         }

 1 int cou = 3;
 2 string uit = string.Empty;
 3 int cou = int.Parse(dt.Rows[0]["小数位数"].ToString());
 4 if (cou == 0)
 5 {
 6     uit = "1";
 7 }
 8 else
 9 {
10     uit = "0.";
11     for (int i = 1; i < cou; i++) 
12     uit += "0";
13     uit += "1";
14 }
15  
16 Jinyi(num, decimal.Parse(uit));
17 Round(num, decimal.Parse(uit));
18 Quzheng(num, decimal.Parse(uit));