Calculate age from two dates vb.net

Question

I am trying to calculate age from dates. This works fine on the server computer but not on a particular client where it report error that "The string 07/21/2016 cannot be converted to a date". I found out that the locale of the server was set to en-US and the client with error locale is set to en-UK. I tried the code below to make the age calculation possible no matter the system locale but it has not worked.

Dim var as string = "07/30/2010"
Dim dob As String = Format(CDate(var & " 01:00:00"), "dd-MM-yyyy hh:mm:ss")
Dim dob1 As Date = DateTime.ParseExact(dob, "dd-MM-yyyy hh:mm:ss", System.Globalization.CultureInfo.InvariantCulture)
Dim todayDate As String = Format(Date.Now, "dd-MM-yyyy hh:mm:ss")
Dim todayDate1 As Date = DateTime.ParseExact(todayDate, "dd-MM-yyyy hh:mm:ss", System.Globalization.CultureInfo.InvariantCulture)
lblDob.Text = var & " (" & DateDiff(DateInterval.Year, dob1, todayDate1) - 1 & " yrs)"

Dates are from the database entered via the server, the above date is just to illustrate. — Diamond, Mar 27 '16 at 09:29
and I assume (hope?) they're stored as `DateTime` in the database? Why bother with strings at all? — christophano, Mar 27 '16 at 09:30
Yes, they are but in the format of `07/30/2010`. In the above code, I converted the string to date. — Diamond, Mar 27 '16 at 09:33
If they're stored as DateTime in the database, why bother with strings at all? — christophano, Mar 27 '16 at 09:45
They can, of course, and you're on the right track with parse exact, you just need to know the format. The question is still valid though - why bother with strings at all? — christophano, Mar 27 '16 at 09:48
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/107457/discussion-between-christophano-and-diamond). — christophano, Mar 27 '16 at 10:07

score 3 · Accepted Answer · edited May 23 '17 at 10:28

3

This is how I simplified your code and made it work:

    Dim userBirthDateText = "07/30/2010"
    Dim userBirthDate = Date.ParseExact(userBirthDateText.Replace("/", "-"), "MM-dd-yyyy", Nothing)
    Dim currentDate = Date.Now
    Dim age = Math.Floor(currentDate.Subtract(userBirthDate).TotalDays / 365)

Notice that I replace "/" by "-" in order to bypass the "slash problem" in dates (which is documented here: Why can't DateTime.ParseExact() parse "9/1/2009" using "M/d/yyyy" ).

Also: I am simplifying the part about "how to get the timespan in years" (my simplification: just divide it by 365). If you want to make it more exact, it will need more work: Format A TimeSpan With Years .

edited May 23 '17 at 10:28

Community

1
1

answered Mar 27 '16 at 10:08

Xavier Peña

7,399
9
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Thanks, works perfectly and thanks again for the link. – Diamond Mar 27 '16 at 10:43
It would be simpler to use `Dim userBirthDate = New DateTime(2010, 7, 30)`. – Andrew Morton Mar 27 '16 at 13:09

score 0 · Answer 2 · answered Apr 18 '16 at 11:52

I still had problems with time when using @XavierPena method but a all round method I used that worked in all cases is as follows;

'date can be in any form and this method worked for either US or UK locale
'this method always solve the problem of date settings e.g 9/24/2016 or 09/24/2016
Dim age as string = "07/30/2010"
'age
    Try
        Dim birthDate = Date.ParseExact(age.replace("/", "-"), "MM-dd-yyyy", Nothing)
        Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")

    Catch ex As Exception
        Try
            Dim birthDate = Date.ParseExact(age.replace("/", "-"), "M-dd-yyyy", Nothing)
            Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
        Catch ex2 As Exception
            Try
                Dim birthDate = Date.ParseExact(age.replace("/", "-"), "M-d-yyyy", Nothing)
                Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
            Catch ex3 As Exception
                Try
                    Dim birthDate = Date.ParseExact(age.replace("/", "-"), "MM-d-yyyy", Nothing)
                    Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
                Catch ex4 As Exception
                    Try
                        Dim birthDate = Date.ParseExact(age.replace("/", "-"), "dd-MM-yyyy", Nothing)
                        Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
                    Catch ex5 As Exception
                        Try
                            Dim birthDate = Date.ParseExact(age.replace("/", "-"), "dd-M-yyyy", Nothing)
                            Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
                        Catch ex6 As Exception
                            Try
                                Dim birthDate = Date.ParseExact(age.replace("/", "-"), "d-M-yyyy", Nothing)
                                Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
                            Catch ex7 As Exception
                                Dim birthDate = Date.ParseExact(age.replace("/", "-"), "d-MM-yyyy", Nothing)
                                Return (Math.Floor(Date.Now.Subtract(birthDate).TotalDays / 365) & " yrs")
                            End Try
                        End Try

                    End Try
                End Try
            End Try
        End Try

    End Try

score 0 · Answer 3 · answered Nov 09 '21 at 11:10

0

I use this code and it works for me.

Dim DoB as DateTime=dateTimePickerDoB.value.toshortdatestring
Dim DtNow as DateTime=Now.ToshortDatestring
Dim Age as Integer=Datediff(DateInterval.Year,DoB,DtNow)
txtage.text=age

answered Nov 09 '21 at 11:10

Sir-me

1

Calculate age from two dates vb.net

3 Answers3