?
Solved

How do I calculate due date with whole months?

Posted on 2009-05-07
4
Medium Priority
?
631 Views
Last Modified: 2013-12-17
I'm trying to calculate the due date of an invoice, and I have a date of invoice, days to due date (100) and I need to calculate due date with whole months:

For example:
if date of invoice = 07/05/2009 and days of due date = 120, then the due date calculated = 07/09/2009 (4 months exactly -whole months-).
My code:
 
DateTime invoiceDate=System.DateTime.Now();
int numberOfDays=100;
int numberOfMonths;
int restOfNumberOfDays;
Date dueDate;
 
if(wholeMonths)
{
    numberOfMonths = numberOfDays % 30;
    dueDate = dt.AddMonths(numberOfMonths);
    restOfNumberOfDays = numberOfDays - (numberOfMonths * 30);
    dueDate = dueDate.AddDays(restOfNumberOfDays);
}
 
This code would be correct if the month had 30 days long.

Open in new window

0
Comment
Question by:ReaL10
  • 2
4 Comments
 
LVL 16

Accepted Solution

by:
CuteBug earned 900 total points
ID: 24324354
There is a DateDiff method in Visual Basic which returns the value in months.

Just go through this site for details
http://www.csharpfriends.com/Forums/ShowPost.aspx?PostID=52580

The decompiled code for DateDiff is provided there...

you need to convert it to C#.
Here is the code...
Public Shared Function DateDiff(ByVal Interval As DateInterval, ByVal Date1 As DateTime, ByVal Date2 As DateTime, ByVal Optional DayOfWeek As FirstDayOfWeek = 1, ByVal Optional WeekOfYear As FirstWeekOfYear = 1) As Long
Dim currentCalendar As Calendar
Dim span As TimeSpan = Date2.Subtract(Date1)
Select Case Interval
Case DateInterval.Year
currentCalendar = DateAndTime.CurrentCalendar
Return CLng((currentCalendar.GetYear(Date2) - currentCalendar.GetYear(Date1)))
Case DateInterval.Quarter
currentCalendar = DateAndTime.CurrentCalendar
Return CLng(((((currentCalendar.GetYear(Date2) - currentCalendar.GetYear(Date1)) * 4) + ((currentCalendar.GetMonth(Date2) - 1) / 3)) - ((currentCalendar.GetMonth(Date1) - 1) / 3)))
Case DateInterval.Month
currentCalendar = DateAndTime.CurrentCalendar
Return CLng(((((currentCalendar.GetYear(Date2) - currentCalendar.GetYear(Date1)) * 12) + currentCalendar.GetMonth(Date2)) - currentCalendar.GetMonth(Date1)))
Case DateInterval.DayOfYear, DateInterval.Day
Return CLng(Math.Round(Conversion.Fix(span.TotalDays)))
Case DateInterval.WeekOfYear
Date1 = Date1.AddDays(CDbl((0 - DateAndTime.GetDayOfWeek(Date1, DayOfWeek))))
Date2 = Date2.AddDays(CDbl((0 - DateAndTime.GetDayOfWeek(Date2, DayOfWeek))))
Return (CLng(Math.Round(Conversion.Fix(Date2.Subtract(Date1).TotalDays))) / 7)
Case DateInterval.Weekday
Return (CLng(Math.Round(Conversion.Fix(span.TotalDays))) / 7)
Case DateInterval.Hour
Return CLng(Math.Round(Conversion.Fix(span.TotalHours)))
Case DateInterval.Minute
Return CLng(Math.Round(Conversion.Fix(span.TotalMinutes)))
Case DateInterval.Second
Return CLng(Math.Round(Conversion.Fix(span.TotalSeconds)))
End Select
Throw New ArgumentException(Utils.GetResourceString("Argument_InvalidValue1", New String() { "Interval" }))
End Function 

Open in new window

0
 
LVL 16

Assisted Solution

by:CuteBug
CuteBug earned 900 total points
ID: 24324366
I think this is what they are doing for difference in months

private static int monthDifference(DateTime startDate, DateTime endDate)
{
int monthsApart = 12 * (startDate.Year - endDate.Year) + startDate.Month - endDate.Month;
return Math.Abs(monthsApart);
}

Open in new window

0
 
LVL 4

Assisted Solution

by:cauos
cauos earned 300 total points
ID: 24324389
there is an already method to add days to datetime objct in .Net, all what you have to do is add number of days to the method AddDays()

DateTime duedate = DateTime.Now
duedate = duedate.AddDays(120)

0
 
LVL 9

Assisted Solution

by:tculler
tculler earned 300 total points
ID: 24325458
Well, if you want every month to be exactly 30 days, you could use the following method:
System.DateTime CalculateDueDate(System.Int32 myDaysUntilDue)
{
     return System.DateTime.Now.AddMonths(myDaysUntilDue / 30);
}

Open in new window

0

Featured Post

Vote for the Most Valuable Expert

It’s time to recognize experts that go above and beyond with helpful solutions and engagement on site. Choose from the top experts in the Hall of Fame or on the right rail of your favorite topic page. Look for the blue “Nominate” button on their profile to vote.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

More often than not, we developers are confronted with a need: a need to make some kind of magic happen via code. Whether it is for a client, for the boss, or for our own personal projects, the need must be satisfied. Most of the time, the Framework…
Today I had a very interesting conundrum that had to get solved quickly. Needless to say, it wasn't resolved quickly because when we needed it we were very rushed, but as soon as the conference call was over and I took a step back I saw the correct …
Despite its rising prevalence in the business world, "the cloud" is still misunderstood. Some companies still believe common misconceptions about lack of security in cloud solutions and many misuses of cloud storage options still occur every day. …
As many of you are aware about Scanpst.exe utility which is owned by Microsoft itself to repair inaccessible or damaged PST files, but the question is do you really think Scanpst.exe is capable to repair all sorts of PST related corruption issues?
Suggested Courses
Course of the Month16 days, 1 hour left to enroll

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question