Question

I was going through some reports that were supposed to be displaying 2/1/2009 – 2/28/2009, but instead was displaying 2/1/2009 – 3/1/2009. I have narrowed the bug down to this code, any suggestions?

Function GetMonthLastDate(ByVal sDateTime As DateTime)     Try         Dim strArrMonth() As String = {'', '31', '29', '31', '30', '31', '30', '31', '31', '30', '31', '30', '31'}         Dim days As Integer         If sDateTime.Month = 2 Then             If sDateTime.Year Mod 400 = 0 Then Return sDateTime.AddDays(28)             If sDateTime.Year Mod 100 = 0 Then Return sDateTime.AddDays(27)             If sDateTime.Year Mod 4 = 0 Then Return sDateTime.AddDays(28)         End If         days = strArrMonth(sDateTime.Month)         Return Format(sDateTime.AddDays(days - 1), 'MM/dd/yyyy')     Catch ex As Exception         Response.Write('<script>alert('' & ex.Message & '');</script>')     End Try End Function 

Answer 1

This is some seriously convoluted code for what it’s doing. You can accomplish the same thing like this:

Function GetMonthLastDate(ByVal sDateTime As DateTime)   Dim nextMonth As DateTime = sDateTime.AddMonths(1)   Return New DateTime(nextMonth.YearPart, nextMonth.MonthPart, 1).AddDays(-1) End Function 

That might be a little cryptic, but it should work and can be expanded for clarity.