如何计算周别

计算周别的代码如下：

1. private void CalWeekNo()
2.         {
3.             string base_day, curr_day,base_day_of_week;
4.             DateTime DT_base;
5.             int base_day_of_year,curr_day_of_year;
7.             base_day = "1/1/" + dateTimePicker1.Value.Year;
8.             curr_day = dateTimePicker1.Value.ToString();
10.             DT_base = DateTime.Parse(base_day);
11.             base_day_of_year = DT_base.DayOfYear;
12.             curr_day_of_year = dateTimePicker1.Value.DayOfYear;
13.             base_day_of_week = DT_base.DayOfWeek.ToString();
15.             int day_dif;
16.             day_dif = curr_day_of_year - base_day_of_year;
18.             switch (base_day_of_week)
19.             {
20.                 case "Monday":                    
21.                     weekNo_curr = day_dif / 7 + 1;
22.                     break;
23.            
24.                 case "Tuesday":
25.                     weekNo_curr = (day_dif+1) / 7 + 1;
26.                     break;
27.            
29.                 case "Wednesday":
30.                     weekNo_curr = (day_dif + 2) / 7 + 1;
31.                     break;
32.          
33.          
34.                 case "Thursday":
35.                     weekNo_curr = (day_dif + 3) / 7 + 1;
36.                     break;
37.           
38.                 case "Friday":
39.                     weekNo_curr = (day_dif + 4) / 7 + 1;
40.                     break;
41.          
42.                 case "Saturday":
43.                     weekNo_curr = (day_dif + 5) / 7 + 1;
44.                     break;
45.          
46.                 case "Sunday":
47.                     weekNo_curr = (day_dif + 6) / 7 + 1;
48.                     break;
49.             }
51.            
52.         }