How can I display an age as Years, Months, Days from a datetime picker value. Eg:
Datetimepicker value = #1/11/2014#
Today = #1/12/2015#.
The final result would be "1 Year, 0 Months, 1Day(S)". But getting that result is more than just subtracting the DateTime.Year values and so forth. Does anybody know a mathematics formula or mathematics calculation about that?
Here is a DateTimeSpan Type which returns an object like a TimeSpan representing the Yrs, Months, Days elapsed between 2 dates. It loops thru the time units to increment them until the smaller date matches the larger. The resulting increments are then returned in a new DateTimeSpan object.
Public Structure DateTimeSpan
Private _Years As Integer
Public ReadOnly Property Years As Integer
Get
Return _Years
End Get
End Property
Private _Months As Integer
Public ReadOnly Property Months As Integer
Get
Return _Months
End Get
End Property
Private _Days As Integer
Public ReadOnly Property Days As Integer
Get
Return _Days
End Get
End Property
Private _Hours As Integer
Public ReadOnly Property Hours As Integer
Get
Return _Hours
End Get
End Property
Private _Minutes As Integer
Public ReadOnly Property Minutes As Integer
Get
Return _Minutes
End Get
End Property
Private _Seconds As Integer
Public ReadOnly Property Seconds As Integer
Get
Return _Seconds
End Get
End Property
Private _MilliSeconds As Integer
Public ReadOnly Property MilliSeconds As Integer
Get
Return _MilliSeconds
End Get
End Property
' the ctor for the result
Private Sub New(y As Integer, mm As Integer, d As Integer,
h As Integer, m As Integer, s As Integer,
ms As Integer)
_Years = y
_Months = mm
_Days = d
_Hours = h
_Minutes = m
_Seconds = Seconds
_MilliSeconds = ms
End Sub
' private time unit tracker when counting
Private Enum Unit
Year
Month
Day
Complete
End Enum
Public Shared Function DateSpan(dt1 As DateTime,
dt2 As DateTime) As DateTimeSpan
' we dont do negatives
If dt2 < dt1 Then
Dim tmp = dt1
dt1 = dt2
dt2 = tmp
End If
Dim thisDT As DateTime = dt1
Dim years As Integer = 0
Dim months As Integer = 0
Dim days As Integer = 0
Dim level As Unit = Unit.Year
Dim span As New DateTimeSpan()
While level <> Unit.Complete
Select Case level
' add a year until it is larger;
' then change the "level" to month
Case Unit.Year
If thisDT.AddYears(years + 1) > dt2 Then
level = Unit.Month
thisDT = thisDT.AddYears(years)
Else
years += 1
End If
Case Unit.Month
If thisDT.AddMonths(months + 1) > dt2 Then
level = Unit.Day
thisDT = thisDT.AddMonths(months)
Else
months += 1
End If
Case Unit.Day
If thisDT.AddDays(days + 1) > dt2 Then
thisDT = thisDT.AddDays(days)
Dim thisTS = dt2 - thisDT
' create a new DTS from the values caluclated
span = New DateTimeSpan(years, months, days, thisTS.Hours,
thisTS.Minutes, thisTS.Seconds,
thisTS.Milliseconds)
level = Unit.Complete
Else
days += 1
End If
End Select
End While
Return span
End Function
End Structure
Dim dts As DateTimeSpan = DateTimeSpan.DateSpan(#2/11/2010#, #10/21/2013#)
Console.WriteLine("{0} Yrs, {1} Months and {2} Days",
dts.Years.ToString, dts.Months.ToString, dts.Days.ToString)
This will give the same result:
Dim dtStart As DateTime = #2/11/2010#
Dim dtEnd As new DateTime(2013, 10, 21)
' this is NOT a date and wont work:
Dim myDt = "2/11/2010" ' its a string!
Dim dts As DateTimeSpan = DateTimeSpan.DateSpan(dtEnd, dtStart)
Result: 3 Yrs, 8 Months and 10 Days
Notes:
- It works only on proper DateTime types, not strings which look like dates. Use literals (#...#) or DateTime variables. When using a DateTimePicker, use .Value not .Text.
- It does not do negative values, so the order of values passed does not matter
- When calculating, it increments a DateTime variable so, it should properly account for leap days
This is based on some C# code I found long ago in a blog (or perhaps even from an SO answer or question). Cant find it just now to cite the original.
This method is very straight forward and simple.
Creating loops and class properties is not needed.
This will work with both real Date types and Strings that are dates:
'Date Picker Value
Dim dBirthDate As Date = "#01/11/2014#"
'Today
Dim dToday As Date = "#01/12/2015#"
Dim dBirthDay As Date
Dim sYears As String
Dim sDays As String
Dim sMonths As String
Dim sResults As String
sYears = DateDiff(DateInterval.Year, dBirthDate, dToday)
dBirthDay = dBirthDate.AddYears(sYears)
sMonths = DateDiff(DateInterval.Month, dBirthDay, dToday)
sDays = DateDiff(DateInterval.Day, dBirthDay, dToday)
sResults = sYears & " Year " & sMonths & " Months " & sDays & " Day(s)"
Example result: 1 Year 0 Months 1 Day(s)
This method uses loops to work this backwards, but I believe this is the only accurate way to do this and get the values always correct. This is because it is more complicated than you might think - you need to adjust for leap years, etc.
''' <summary>
''' Finds the Years Months and Days Span between two dates
''' </summary>
''' <param name="fromDate"></param>
''' <param name="toDate"></param>
''' <returns>A String formatted as i Years j Months k Days</returns>
''' <remarks></remarks>
Public Shared Function GetDateSpanText(ByVal fromDate As DateTime, Optional toDate As DateTime = Nothing) As String
Dim years As Integer = 0, months As Integer = 0, days As Integer = 0
If toDate = Nothing Then toDate = DateTime.Now
Do Until toDate.AddYears(-1) < fromDate
years += 1
toDate = toDate.AddYears(-1)
Loop
Do Until toDate.AddMonths(-1) < fromDate
months += 1
toDate = toDate.AddMonths(-1)
Loop
Do Until toDate.AddDays(-1) < fromDate
days += 1
toDate = toDate.AddDays(-1)
Loop
Return String.Format("{0} Year(s) {1} Month(s) {2} Day(s)", years, months, days)
End Function
Usage:
Debug.WriteLine(GetDateSpanText(#1/11/2014#))
Prints:
1 Year(s) 0 Month(s) 1 Day(s)
you must add this to get a complete result: sDays = (DateDiff(DateInterval.Day, dBirthDay, dToday)) - sMonths * 30
