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Skystone Software
http://www.SkystoneSoftware.comScott Waletzko's Blog
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Calculating Number of Days from a Series of Dates
Published: 4/15/2009 |
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As so often happens, a lot of code I write is in response to a question posted over at the VBCity.com forums. This is one such code snippet - the question was how to calculate the total span of time from the earliest time to the latest time given a set of dates. Enjoy!
VB:
Public Class DateRange
Private _fromDate As DateTime
Private _toDate As DateTime
Private _timeSpan As TimeSpan
Public Sub New(ByVal FromDate As DateTime, ByVal ToDate As DateTime)
' validate...
If (FromDate.CompareTo(ToDate) <>-1) Then
Throw New System.Exception("The FromDate must be earlier than the ToDate.")
End If
' store..
_fromDate = FromDate
_toDate = ToDate
_timeSpan = ToDate.Subtract(FromDate)
End Sub
Public ReadOnly Property FromDate() As DateTime
Get
Return _fromDate
End Get
End Property
Public ReadOnly Property ToDate() As DateTime
Get
Return _toDate
End Get
End Property
Public ReadOnly Property TimeSpan()
Get
Return _timeSpan
End Get
End Property
Public Function IsInRange(ByVal Value As DateTime) As Boolean
Return Value.CompareTo(Me.FromDate) > -1 And Value.CompareTo(Me.ToDate) < 1
End Function
Public Function IntersectsWith(ByVal Value As DateRange) As Boolean
If Me.IsInRange(Value.FromDate) Or Me.IsInRange(Value.ToDate) Then Return True
End Function
Public Sub CombineWith(ByVal Value As DateRange)
' validate...
If Not (Me.IntersectsWith(Value)) Then
Throw New System.Exception("The specified date ranges cannot be combined - they do not overlap.")
End If
' get full range...
If (Me.FromDate.CompareTo(Value.FromDate) = 1) Then
_fromDate = Value.FromDate
End If
If (Me.ToDate.CompareTo(Value.ToDate) = -1) Then
_toDate = Value.ToDate
End If
End Sub
End Class
Here's how to use it:
VB:
Private Sub Test()
Dim dateRanges As New List(Of DateRange)
AddDateRange(dateRanges, New Date(2008, 1, 1), New Date(2008, 1, 15))
AddDateRange(dateRanges, New Date(2008, 1, 10), New Date(2008, 1, 25))
AddDateRange(dateRanges, New Date(2008, 1, 1), New Date(2008, 1, 15))
For Each range As DateRange In dateRanges
Debug.WriteLine(range.ToString())
Next
End Sub
Private Sub AddDateRange(ByVal Ranges As List(Of DateRange), ByVal FromDate As DateTime, ByVal ToDate As DateTime)
'create new date range...
Dim combined As Boolean = False
Dim range As New DateRange(FromDate, ToDate)
For Each item As DateRange In Ranges
If item.IntersectsWith(range) Then
item.CombineWith(range)
combined = True
Exit For
End If
Next
If Not combined Then Ranges.Add(range)
End Sub
...and the output:
1/1/2008 12:00:00 AM to 1/25/2008 12:00:00 AM
Questions or Comments? .
VB to C# and C# to VB translation provided by Instant C# and Instant VB.
