calculate number of months between two dates - vb.net

Hi,
I was wondering if you can help.
I have two date strings and I wish to be able to calculate the number of months between them.
Note the dates are for different years.
Many thanks
Mark :)

0 markbpriv 9/27/2007 11:08:18 AM

I suppose you can cast them to DateTime structures. Then you can do something like the following

//d2 and d are your datetime structures
//we suppose that each month has 30 days
TimeSpan t = d2 - d; 
double months = Math.Round(t.TotalDays /30);
It's not exact however (since not all months have thirty days) 
Plese, do not forget to click "Mark as Answer" on the post that helped you. Thanx!

My blog: Scenes From A Developer Memory

0 dt008 9/27/2007 11:55:15 AM

Dim d1 As DateTime = New DateTime(2002, 1, 1)
Dim d2 As DateTime = New DateTime(2000, 10, 1)
Dim M As Integer = Math.Abs((d1.Year - d2.Year))
Dim months As Integer = ((M * 12)  + Math.Abs((d1.Month - d2.Month)))
Bashar Kokash, Blog

0 BasharKokash 9/27/2007 12:10:25 PM

greeting there here's your small function code
Public Sub subdate(ByVal date1 As String, ByVal date2 As String) 
' note that the date is in the format mm/dd/yyyy you can reformat
Dim dt1 As Date = Date.Parse(date1) 
Dim dt2 As Date = Date.Parse(date2)

' here we suppose the month is 30 days
YourTextBox.Text = Math.Abs(CInt(dt1.Subtract(dt2).TotalDays / 30)) 
'the abs is absolute value if the first is greater than the second

End Sub
 
 
hope being helpfull..........
SALO   ZA  SOLO

0 SaloZaSolo 9/27/2007 12:11:46 PM

Hi,
Thanks for this.
 Any idea how I can accomodate months that are not 30 days?
 Cheers
 Mark :)

0 markbpriv 9/27/2007 12:27:36 PM

Couldn't you just use DateDiff()
 

DateDiff(DateInterval.Month, date1, date2)
Life would be so much easier if we only had the source code.

0 jfmccarthy 9/27/2007 3:23:57 PM

 Public Function monthDifference(ByVal startDate As DateTime, ByVal endDate As DateTime) As Integer 
Dim t As TimeSpan = endDate - startDate
Dim difference As Integer = t.Days
Dim months As Integer = Math.Floor(difference / 30.475)
Return months 

End Function
From : http://forums.asp.net/p/1159955/1914676.aspx
 
HTH,
Suprotim Agarwal
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0 Suprotim 9/27/2007 3:34:03 PM

 markbpriv:
  Any idea how I can accomodate months that are not 30 days?
 
My previous reply do exactly what you want.
Bashar Kokash, Blog

0 BasharKokash 9/27/2007 7:55:54 PM

Hi,
Yes this all worked.
Thanks very much.
Cheers
Mark :)

0 markbpriv 9/28/2007 4:33:25 PM

 
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I create a better and more accurate method.

Try this people it's the best.




 
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/// 


/// Methord to calculate no of months between two dates

/// Creater:- Sasanka Fernando

/// Email:- wsdesa@gmail.com

/// 


/// 

/// 

///  number of months as an integer 

public
int monthDifference(DateTime
startDate, DateTime endDate)

{

/// This is to set date to "0001/01/01"

DateTime systemStartDate = new
DateTime();

 

/// Time span to set the total time
difference

TimeSpan timeDifference;

 

///This if condition to avoid the minus
value for Time difference

if (endDate > startDate)

{

timeDifference =
endDate.Subtract(startDate);

}

else

{

timeDifference =
startDate.Subtract(endDate);

  
   }

 

///This is to generate a date from the
systemStartDate  

DateTime generatedDate =
systemStartDate.Add(timeDifference);

 

///Substract 1 because the systemStartDate
is "0001/01/01"

int noOfYears = generatedDate.Year - 1;

int noOfMonths = generatedDate.Month - 1;

 

noOfMonths = noOfMonths + (noOfYears * 12);

 

return noOfMonths;

}

0 wsdesa 4/28/2009 8:23:11 AM