Leap year problem

[hallsers]

Here is the problem i am having: -

When a user logs in, on page load it will take the dob of all users in a stored friends list and compare them against the following conditions - To display any friends with a birthday inside the next 3 days, taking into account leap years for some1 born on the 29th of feb to be born on 28th in non leap years and also to display their age with the reminder. Here is code i have picked up so far.

1.  vb.net
    Public Function CalculateAge(ByVal birthday As DateTime) As Integer
     Dim bd As DateTime
     Try
      ' Birthday this year
      bd = New DateTime(DateTime.Today.Year, birthday.Month, birthday.Day)
     Catch
      ' no valid date, must be a leap year Then....
      ' set birthday one day futher in time.
      birthday = birthday.AddDays(1)
      bd = New DateTime(DateTime.Today.Year, birthday.Month, birthday.Day)
     End Try
     Dim age As Integer = DateTime.Today.Year - birthday.Year
     If (DateTime.Today < bd) Then age -= 1
 
     Return age
    End Function

There is a problem with birthdays on Feb 29th in leap year, the statement: new DateTime(DateTime.Today.Year, birthday.Month, birthday.Day);
throws an exception.
If this year is NOT a leap year, you must first convert a birthday of 2/29/ to 2/28 (or 3/1 if you think that's when the person should be a year older!).

 2. 
Private Sub LeapYearCheck()     
Dim bLeapYear AsBoolean      
bLeapYear = Date.IsLeapYear(Now.Year)     
MessageBox.Show(bLeapYear)      
bLeapYear = Date.IsLeapYear(2004)     
MessageBox.Show(bLeapYear) End Sub

3.
Function IsLeapYear(ByVal SomeValue As Variant) As Boolean
    On Error GoTo LocalError
    Dim intYear As Integer
    'The trick here is make sure that we get an integer
    'The 3 Golden rules are:
    'True if it is divisible by 4
    'False if it is divisible by 100
    'TRUE if it is divisble by 400
    If IsDate(SomeValue) Then
        intYear = CInt(Year(SomeValue))
    Else
        'try and get an integer from the parse
        'does not matter if we get an error
        'because the error trap will catch it
        intYear = CInt(SomeValue)
    End If
    If TypeName(intYear) = "Integer" Then
        IsLeapYear = ((intYear Mod 4 = 0) And _
          (intYear Mod 100 <> 0) Or (intYear Mod 400 = 0))
    End If
Exit Function
LocalError:
    IsLeapYear = False
End Function

I know i can use some fo this code to achieve this but i am unsure of the arrangement, any ideas?


Cheers

[kenobewan]

@hallsers
I take this to mean that you have copied & pasted the code. It may better to spend the time learning how to do it and then you have a good idea next time.

There are many online resources, books or courses that can help. Try searching the site also as I'm sure this question has come up before.

[hallsers]

No this is code that i have found myself on the internet and am unsure as to the arrangment of such code to my specific problem. I am unsure as to what code i can use in the problem and which variables can be used or modified to suit the situation. Any help would be appreciated. Thanku

[hallsers]

any leap year examples on the site are in another language and not vb.net
I have attempted coding this into my Active Server Page with no luck so far.

any ideas would be welcome or a view on which way to approach this??

[balabaster]

This leads to the interesting question of "When does someone who is born on February 29th celebrate their birthday in non-leap years?"