Add Program Functionality

Part II
Add Program Functionality

The next step in this process is to add most of our functionality to our CalendarCode ( ) function. This is how one normally goes about writing a normal GUI program so I will not go into a lot of detail here on what each part of the program accomplishes. Basically we are adding all the elements that will make the program work according to our goals stated in the introduction. These goals are accomplished by adding code to CalendarCode ( ) and/or by adding specific functions.

Add date functions
I added a few date functions that will be used to calculate any selected day, month, or year. Several of these functions came from the XB mailing list (thanks). I added:

DateToGregorianDayNumber ( )
Gregorian ( )
Julian ( )
Weekday ( )

Create SUBs in CalendarCode ( )
The next step involves adding all of the data and event processing subroutines. I have added SUBs that will do calculations to get the current day, then display the proper dates in each of the day kid grids. Then I added code to change the day and month using the arrow PressButtons. And finally, I wanted to highlight the currently selected day when it is clicked by the left mouse button.

Changes to SUB Selection
It might of interest to point out how I compressed the SUB Selection subroutine. Our code generated by the Toolkit creates a selection for EACH kid grid in our program. So we had 58 kids in our SELECT CASE statement. I changed the SELECT CASE kid to SELECT CASE TRUE and changed the CASE statements as follows:

SELECT CASE TRUE
CASE kid = $MonthLeftArrowPressB   : DEC month
                                       IF month = 0 THEN
                                         month = 12
                                         DEC year
                                       END IF
CASE kid = $MonthRightArrowPressB : INC month
                                       IF month > 12 THEN
                                         month = 1
                                         INC year
                                       END IF
CASE kid = $YearLeftArrowPressB    : DEC year
CASE kid = $YearRightArrowPressB   : INC year
CASE kid >= $Day1                  : GOSUB DaySelection
                                       EXIT SUB
END SELECT

Our calendar grid looks basically the same as in Part I, but now it works and the currently selected day is highlighted in yellow.

It is not the intent of this discussion to go over the code in this part and so I will leave it to the reader to go through the code in CalendarCode ( ) on their own. The code for this section of Part II can be found in calendar1.x.

Continue Adding new functionality to CalendarCode ( )
At this point there are few things that I needed to add or correct. First, I wanted to grey out the days shown in the calendar that where not part of the current month. Next, I had to add code to update the labels so that they reflected the currently selected date.

Then things started to get a bit tricky. I wanted to be able to select a day that was not in the current month. This would change the calendar to the next or previous month, highlight the selected day, and update all the labels.

Another item that needed work involved selecting months or years. In order to keep accurate track of the day grid selection, I decided that all changes to the year or month by the arrow PressButtons would set the current day to the 1st of the month.

And finally, I added the Today PushButton in order to make it easy to return to the current day. Here is what the next version looks like. The code for this version is in calendar2.x.

In the Next Part

At this point, we now have a working program so we want to go on to the next crucial step of creating a new grid function.

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