主题：日期返回第几周

1、法定节假日，你需要另外做一张表。

2、第几周，你要这样处理

Dim d As Date = "2017-1-9"

Dim gc As System.Globalization.GregorianCalendar = new System.Globalization.GregorianCalendar()
Dim weekOfYear As Integer = gc.GetWeekOfYear(d,System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Monday)
Return weekOfYear