[DUG] DateTimePicker

[Jolyon Smith]

TDateTimePicker internally initialises its DateTime to "Now" - changes to
the date-part of the value presumably do not alter the time-part (unless
modifying date AND time via the DateTime value).  The different time-parts
in your pickers presumably reflects different constructor execution times
(yielding slightly different Now() results and therefore different time-part
values).

Two ways (at least) to skin this particular feline spring to mind: 

1. If you only ever work with the Date of these pickers, you could
initialise each to a known, consistent time-value (this then shouldn't
change unless you subsequently change the time-value in some other way)

2. Specifically exclude the time-part by Trunc()'ing the Date in any
comparisons.  The Date property itself only does a hard-typecast, not a
conversion and since TDate is simply a distinct-type alias for TDateTime
this merely propagates and preserves the time-part of the underlying
datetime into the supposedly "date only" TDate value.


Hope that helps.



-----Original Message-----
From: delphi-bounces at delphi.org.nz [mailto:delphi-bounces at delphi.org.nz] On
Behalf Of John Bird
Sent: Tuesday, 29 June 2010 13:42
To: NZ Borland Developers Group - Delphi List
Subject: [DUG] DateTimePicker

When a TDateTime is set from a DateTimePicker that is being used for Date 
selections what is set for the time component?  Or is it random?   I am 
wondering because two different pickers seem to return unrelated times and 
it looks like  I have to do some testing and correcting.

And for testing - I think that a test such as

if DatePicker1.date = date then......

might not be a reliable test (if both are effectively floating point)

This is D5 in case later versions have smarter testing....

John 


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