Question

I need to calculate in hours how much time has elapsed from when a record was created to the current time. The hard part is I need to exclude weekend times from this.

I have been working on this for quite a while and I am just lost. Here is what I have so far. Thank you in advance for your help.

   Dim MyStartTime As DateTime = "2010-08-09 07:00:00.000"
    Dim MyEndTime As DateTime = DateAdd("h", -1, Now())

    Dim MyHours As Integer = 0

    If Weekday(MyStartTime) > 1 And Weekday(MyStartTime) < 6 Then

        MyHours = DateDiff("h", MyStartTime, MyEndTime)

    ElseIf Weekday(MyStartTime) = 6 Then
        Dim EndTime
        date1.Date()
        MyHours = DateDiff("h", MyStartTime, MyEndTime)


    End If

    lblHours1.Text = MyHours

What algorithm in VB.NET would best suit this calculation?

Answer 1

Here’s one method:

Determine the TimeSpan in hours for the entire range.

Determine if the start and end falls on a weekend. Subtract the appropriate hours. If starting on a weekend, remove the hours until Monday at 00:00. If ending on a weekend, subtract hours elapsed since Saturday at 00:00. Then account for any full weekend days falling in between.

This requires implementing 3 methods to return a number of hours to be subtracted. If none, just return 0 on each:

NumberOfHoursBetweenDateAndNextMonday – when starting on a weekend day.
NumberOfHoursBetweenDateAndEarliestSaturday – when ending on a weekend day.
NumberOfFullWeekendHoursWithinRange – all those days in between.

Dim MyHours As TimeSpan = MyEndTime - MyStartTime

'account for start being on a weekend
If (MyStartTime.DayOfWeek = vbSaturday Or vbSunday) Then
    'subtract number of hours until Monday at 00:00
    MyHours -= NumberOfHoursBetweenDateAndNextMonday(MyStartTime)

End If

If (MyEndTimeTime.DayOfWeek = vbSaturday Or vbSunday) Then
   'subtract number of hours elapsed after Saturday at 00:00
   MyHours -= NumberOfHoursBetweenDateAndEarliestSaturday(MyEndTime)
End If

MyHours -= NumberOfFullWeekendHoursWithinRange(MyStartTime, MyEndTime)