Converting days to yy/mm/dd (Resolved)

[SuperSparks]

Hi all,

Having had great success with what I thought were going to be the hard bits, I left what I thought was going to be trivially easy till last. I should have known better

Dy = Math.Abs(DateDiff(DateInterval.Day, DateOne, DateTwo))

That nicely gives the result in days. What I want is the result in Years, Months, and Days. I'm just about to give up and write a function or a class to do it, but before I do I want to make sure that I'm not missing some easy way to convert days into Y,M,D. I've been through MSDN Library looking at Date, DateTime, TimeSpan, DatePart until my eyes glazed over, but I can't figure out an easy way of doing it.

Any ideas?

[dynamic_sysop]

here's a link to an example i made ( 2nd post down , as Csharp ) , it does the years / months , all you need to add to it is the days ( same principle as the year / month )
[ Link to thread ]

[Dmyze]

Timespan should do it.

        Dim ts As TimeSpan = New TimeSpan(3000, 0, 0, 0)
        MsgBox(ts.TotalDays)
        MsgBox(ts.TotalHours)
        MsgBox(ts.TotalMinutes)
        MsgBox(ts.TotalSeconds)
        MsgBox(ts.TotalMilliseconds)

oh wait you want months..

[SuperSparks]

Many thanks, guys

That link of dynamic_sysop's looks like it will work nicely. Rather annoyingly I'd already tried something along the same lines, but couldn't get it to work, so I convinced myself that I was barking up the wrong tree. That'll teach me.

Dynamic, I was interested that you said that DateDiff was a VB6 leftover in the other thread - I've used it elsewhere in my my code and I'm not happy with it. I'm trying hard to do things the .NET way, but MSDN Library doesn't seem to differentiate between the old and the new. Is there a list of what is legacy stuff that I can refer to anywhere?

[dynamic_sysop]

these are the visual basic functions / classes that exist in vb.net , but are left over ( use a reference to visual basic )
Visual Basic Run-Time Library Members

[SuperSparks]

Excellent, thank you kindly. I'll send you a few hours of virtual sleep by way of thanks

[SuperSparks]

After many hours of clicking the Step-into button to try and work out all the logic errors, here is the finished code block. It will take any two dates and display the difference in Years, Months and Days. Hopefully it will come in useful to someone else:

Private Function Y_M_D_Diff(ByVal DateOne As DateTime, ByVal DateTwo As DateTime) As String
        Dim Year, Month, Day As Integer
 
        ' Function to display difference between two dates in Years, Months and Days, calling routine ensures that DateOne is always smaller than DateTwo
        If DateOne <> DateTwo Then                                          ' If both dates the same then exit with zeros returned otherwise a difference of one year gets returned!!!
            ' Years
            If DateTwo.Year > DateOne.Year Then                       ' If year is the same in both dates, an out of range exception is thrown!!!
                Year = DateTwo.AddYears(-DateOne.Year).Year       ' Subtract DateOne years from DateTwo years to get difference
            End If
 
            ' Months
            Month = DateTwo.AddMonths(-DateOne.Month).Month         ' Subtract DateOne months from DateTwo months
            If DateTwo.Month <= DateOne.Month Then                        ' Decrement year by one if DateTwo months hasn't exceeded DateOne months, i.e. not full year yet
                If Year > 0 Then Year -= 1
            End If
 
            ' Days
            Day = DateTwo.AddDays(-DateOne.Day).Day                         ' Subtract DateOne days from DateTwo days
            If DateTwo.Day <= DateOne.Day Then                             ' Decrement month by one if DateTwo days hasn't exceeded DateOne days - not full month yet
                If Month > 0 Then Month -= 1
            End If
            If DateOne.Day = DateTwo.Day Then                        ' Avoid silliness like "1 month 31 days" instead of 2 months
                Day = 0                                                                          ' Reset days
                Month += 1                                                                   ' And increment month
            End If
 
            If Month = 12 Then                                                         ' Months value goes up to 12, and we want a maximum of 11, so:
                Month = 0                                                                     ' Reset months to zero
                Year += 1                                                                       ' And increment year
            End If
            If DateOne.Year = DateTwo.Year AndAlso DateOne.Month = DateOne.Month Then            ' If year and month are the same in DateOne & DateTwo then month = 12 and therefore year has been incremented
                Year = 0                                                                     ' So reset it
            End If
 
        End If         ' DateOne <> DateTwo
 
        Return Year & " years, " & Month & " months, " & Day & " days"                  ' Concatenate string and return to calling routine
 
    End Function       ' Y_M_D_Diff