Answer by Mohammad Ali for Difference in months between two dates

Public Class ClassDateOperation    Private prop_DifferenceInDay As Integer    Private prop_DifferenceInMonth As Integer    Private prop_DifferenceInYear As Integer    Public Function DayMonthYearFromTwoDate(ByVal DateStart As Date, ByVal DateEnd As Date) As ClassDateOperation        Dim differenceInDay As Integer        Dim differenceInMonth As Integer        Dim differenceInYear As Integer        Dim myDate As Date        DateEnd = DateEnd.AddDays(1)        differenceInYear = DateEnd.Year - DateStart.Year        If DateStart.Month <= DateEnd.Month Then            differenceInMonth = DateEnd.Month - DateStart.Month        Else            differenceInYear -= 1            differenceInMonth = (12 - DateStart.Month) + DateEnd.Month        End If        If DateStart.Day <= DateEnd.Day Then            differenceInDay = DateEnd.Day - DateStart.Day        Else            myDate = CDate("01/"& DateStart.AddMonths(1).Month & "/"& DateStart.Year).AddDays(-1)            If differenceInMonth <> 0 Then                differenceInMonth -= 1            Else                differenceInMonth = 11                differenceInYear -= 1            End If            differenceInDay = myDate.Day - DateStart.Day + DateEnd.Day        End If        prop_DifferenceInDay = differenceInDay        prop_DifferenceInMonth = differenceInMonth        prop_DifferenceInYear = differenceInYear        Return Me    End Function    Public ReadOnly Property DifferenceInDay() As Integer        Get            Return prop_DifferenceInDay        End Get    End Property    Public ReadOnly Property DifferenceInMonth As Integer        Get            Return prop_DifferenceInMonth        End Get    End Property    Public ReadOnly Property DifferenceInYear As Integer        Get            Return prop_DifferenceInYear        End Get    End PropertyEnd Class