TDateTimePicker- to highlight dates

[Anatoly]

Hi!

I need to be able to highlight some dates when the calendar drops down
after a mouse click.

I have found some useful information applicable to component
TMonthCalendar. It is possible to send it a message "MCM_SETDAYSTATE"
the following way:
SendMessage(MonthCalendar1.Handle, MCM_SETDAYSTATE, 3, Longint(@mds));

"mds" is an array that is initialized the following way:
var
mds: array[1..3] of MONTHDAYSTATE;

mds[1] := mds[1] or (1 shl 29);
mds[2] := mds[1] or (1 shl 2);
mds[3] := mds[1] or (1 shl 2);

The result is that the 3-rd of the current and then next months and the
30-ths of the previous month are highlighted with bold font. So far so
good- it works for TMonthCalendar.

Problem: when I try to do the same with TDateTimePicker in its DropDown
event then nothing happens. I get its handle and check that it's not
null and send a message:

CalendarHandle := DateTime_GetMonthCal(DateTimePicker1.Handle);
SendMessage(CalendarHandle, MCM_SETDAYSTATE, 3, Longint(@mds));

Then nothing happens.

Question:
1. How can I highlight the dates I need with a different font (or
color?)in TDateTimePicker?
2. Are there any other way of highlighting that can be used instead of
the one I've been thinking of?

Best regards,
Anatoly

[Remy Lebeau (TeamB)]

"Anatoly" <anat...@gmail.com> wrote in message
news:446c3cc7$1...@newsgroups.borland.com...

> I need to be able to highlight some dates when the calendar
> drops down after a mouse click.

Date/Time Picker controls do not natively support what you are asking for.
That is a Win32 API limitation, not a VCL limitation.

> when I try to do the same with TDateTimePicker in its
> DropDown event then nothing happens.

You cannot send MCM messages to a Date/Time Picker control. Date/Time
Picker controls use DTM messages instead. There is no DTM message for
setting bold days.

> CalendarHandle := DateTime_GetMonthCal(DateTimePicker1.Handle);
> SendMessage(CalendarHandle, MCM_SETDAYSTATE, 3, Longint(@mds));
>
> Then nothing happens.

If you look at the return value of SendMessage(), you will see that it
always returns 0, indicating that the MCM_SETDAYSTATE message is failing.

> How can I highlight the dates I need with a different font (or color?)in
TDateTimePicker?

As far as I know, you can't.

> Are there any other way of highlighting that can be used instead
> of the one I've been thinking of?

The only way is to either use a TMonthCalendar and show/hide it manually, or
else find a third-party Date/Time Picker that supports what you are asking
for.

Gambit

[Justin Levene]

You can't do it because you must set MCS_DAYSTATE in the StyleEx when
creating a MonthCalendar. Microsoft decided, in all of their wisdom,
not do do this for the MonthCalendar in the DateTimePicker. It is a
Windows limitation, not a VCL one. As Windows is not Object Orientated
you can't override this, the only way would be to design a component
from scratch (I did this a few years ago but have lost the code, it also
allowed Nul dates as blank text, if you do one please keep me informed).

Justin