Date calculation

rbuser

I have an end-user report, and am trying to create a OnCalc for a
user-defined variable that will take a date from the data (InvoiceDueDate)
and calculate how many days old that is as of today and display the result
on the report.

For example if the InvoiceDueDate is 05/01/2011, and "today" is 05/06/2011
the answer is 5 days old.

I created a variable, made it integer type, but have no clue what to put in
after the Value = : statement.

I could not find date manipilation examples in help, nor the newsgroup for
RAP.

Thanks in advance.

nicocizik

Hi Diana,

I believe Delphi has a DaysBetween routine that takes two TDateTime
parameters and returns an integer value built-in. Though this routine
is not available in RAP, it would be easy to create a pass-thru function
to add the functionality.

See the main RAP demo located in the \Demos\0. RAP\... directory and the
Developer's Guide for examples of creating pass-thru functions for RAP.

Value := DaysBetween(DataSet['InvoiceDueDate'], Now);


Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Hi Nico,
Thank you for your quick repsonse.

While that is helpful, may I suggest that a function be available in a
future release of RAP to enable the capability for a calculation of
"DaysBetween"?

The solution you present is terrific, but I have to wait for the next
release of our software product to share that functionality with our client
base. With the power of RAP we are able to customize many of our end-user
reports without effecting the overall product release schedules (and all
that goes along with the distribution of a new software release).

Please add this request to the RAP enhancement "wish list" for a future
release.

Many Thanks!

nicocizik

Hi Diana,

Thanks for the feedback. I will add this as a possible enhancement for
a later release.

Another option as a work-around would be to calculate the Days Between
value manually in RAP. TDateTime values are Doubles describing the days
and time (the whole number is the day and the decimal is the time). You
could create a simple RAP routine that subtracts the larger date from
the smaller and truncates the decimal to give you the days between.

Pseudo Code...

function DaysBetween(aNow, aThen: TDateTime): Integer
begin
if aNow < aThen then
Result := Trunc(aThen - aNow)
else
Result := Trunc(aNow - aThen);
end;


Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com