Question

I know that Sql Server has some handy built-in quarterly stuff, but what about the .Net native DateTime object? What is the best way to add, subtract, and traverse quarters?

Is it a bad thing™ to use the VB-specific DateAdd() function? e.g.:

Dim nextQuarter As DateTime = DateAdd(DateInterval.Quarter, 1, DateTime.Now) 

Edit: Expanding @bslorence’s function:

Public Shared Function AddQuarters(ByVal originalDate As DateTime, ByVal quarters As Integer) As Datetime     Return originalDate.AddMonths(quarters * 3) End Function 

Expanding @Matt’s function:

Public Shared Function GetQuarter(ByVal fromDate As DateTime) As Integer     Return ((fromDate.Month - 1) \ 3) + 1 End Function 

Edit: here’s a couple more functions that were handy:

Public Shared Function GetFirstDayOfQuarter(ByVal originalDate As DateTime) As DateTime     Return AddQuarters(New DateTime(originalDate.Year, 1, 1), GetQuarter(originalDate) - 1) End Function  Public Shared Function GetLastDayOfQuarter(ByVal originalDate As DateTime) As DateTime     Return AddQuarters(New DateTime(originalDate.Year, 1, 1), GetQuarter(originalDate)).AddDays(-1) End Function 

Answer 1

I know you can calculate the quarter of a date by:

Dim quarter As Integer = (someDate.Month - 1) \ 3 + 1 

If you’re using Visual Studio 2008, you could try bolting additional functionality on to the DateTime class by taking a look at Extension Methods.