Calculate a Persons Age (VB.NET/ASP.NET)

 1 Public Function GetAge(ByVal Birthdate As System.DateTime, _
 2     Optional ByVal AsOf As System.DateTime = #1/1/1700#) _
 3     As String
 4 
 5         'Don't set second parameter if you want Age as of today
 6 
 7         'Demo 1: get age of person born 2/11/1954
 8         'Dim objDate As New System.DateTime(1954, 2, 11)
 9         'Debug.WriteLine(GetAge(objDate))
10 
11         'Demo 1: get same person's age 10 years from now
12         'Dim objDate As New System.DateTime(1954, 2, 11)
13         'Dim objdate2 As System.DateTime
14         'objdate2 = Now.AddYears(10)
15         'Debug.WriteLine(GetAge(objDate, objdate2))
16 
17         Dim iMonths As Integer
18         Dim iYears As Integer
19         Dim dYears As Decimal
20         Dim lDayOfBirth As Long
21         Dim lAsOf As Long
22         Dim iBirthMonth As Integer
23         Dim iAsOFMonth As Integer
24 
25         If AsOf = "#1/1/1700#" Then
26             AsOf = DateTime.Now
27         End If
28         lDayOfBirth = DatePart(DateInterval.Day, Birthdate)
29         lAsOf = DatePart(DateInterval.Day, AsOf)
30 
31         iBirthMonth = DatePart(DateInterval.Month, Birthdate)
32         iAsOFMonth = DatePart(DateInterval.Month, AsOf)
33 
34         iMonths = DateDiff(DateInterval.Month, Birthdate, AsOf)
35 
36         dYears = iMonths / 12
37 
38         iYears = Math.Floor(dYears)
39 
40         If iBirthMonth = iAsOFMonth Then
41             If lAsOf < lDayOfBirth Then
42                 iYears = iYears - 1
43             End If
44         End If
45 
46         Return iYears
47     End Function