|
|
10 Aug 2007
|
Datetime Helper Functions in VB.Net Programming
In various forums, people often ask questions on simple date and time
conversion for use in their software development. Here are some helper functions in VB.
How to trim the time value from date
Function TrimTimeFromDate(ByVal d As DateTime) As DateTime
Return DateTime.Parse(d.ToShortDateString)
End Function
How to add time value to a date
' Usage newDateTimeVariable=AddTime(dateTimeVariable, "3:15")
Function AddTime (ByVal d As Date, ByVal hhmm As String) As Date
Try
Dim hh As Integer = 0
Dim mm As Integer = 0
If hhmm.IndexOf(":"c) > 0 Then
hh = Integer.Parse(hhmm.Split(":")(0))
mm = Integer.Parse(hhmm.Split(":")(1))
Else
mm = Integer.Parse(hhmm)
End If
If hh > 24 OrElse hh < 0 OrElse mm > 59 OrElse mm < 0 Then
Throw New Exception
End If
Dim result As Date
result = d.AddHours(hh)
result = result.AddMinutes(mm)
Return result
Catch
Throw New ApplicationException("Not a valid time")
End Try
End Function
How to Compare the time portion of two dates
You may want to find out some events which happens after a time of the day, e.g. after 6:00 pm. In this case, you need to compare only
the time portion with this time. .Net does not have time only datatype. You can use the following function to do comparison.
Function CompareTimePortion(ByVal dateWithLargeTimePortion As Date,
_
ByVal dateWithSmallTimePortion As Date) As Boolean
If GetTimePortionValue(dateWithLargeTimePortion) >
_
GetTimePortionValue(dateWithSmallTimePortion) Then
Return True
Else
Return False
End If
End Function
Function GetTimePortionValue(ByVal d As Date) As Long
Return d.Ticks - DateTime.Parse(d.ToShortDateString).Ticks
End Function
How to Get a date's Last Day of Month
Function LastDayOfMonth(ByVal d As DateTime) As DateTime
Return d.AddDays(DateTime.DaysInMonth(d.Year, d.Month) - d.Day)
End Function
How to ensure dd-mm-yy string input of a date not intepreted as mm-dd-yy
Function String2Date(ByVal DDMMYY As String) As DateTime
Return DateTime.Parse(DDMMYY, New System.Globalization.CultureInfo("en-GB"))
End Function
You can also download the code from here.
OTHER POPULAR BLOGS
|