How to Simulate Date Spinners by Using a Set of Buttons

ID: Q137181

The information in this article applies to:

Microsoft FoxPro for Windows, versions 2.5, 2.5a, 2.5b, 2.6, 2.6a

SUMMARY

FoxPro for Windows includes the data entry object called a Spinner control to help users enter numeric data. This article shows you how to create a simulated Date Spinner control to help users choose a date. The technique involves using a set of buttons with a date field to create the simulated Date Spinner control. A third button is included to allow the user to clear the date or set it to the current system date.

MORE INFORMATION

The main function of the Date Spinner buttons is to increase or decrease the value of the date by one or more days. FoxPro supports date arithmetic. Adding a whole number to a date changes the date to the date that is that number of days in the future. Subtracting a whole number from a date changes the date to the date that is that number days in the past.

The example in this article uses three buttons. The Plus and Minus buttons add or subtract one from the date field. If the date field is empty, the buttons set it to the current system date.

The optional third button has two functions. When the date field has a value, the third button displays the letter C to indicate that it will clear the date value. When the date field is empty, the third button displays the letter T to indicate that it will set the day to today's date. This is not a feature you would normally find with a Spinner object, but it can be a handy one for data entry.

Steps to Create Date Spinners by Using Buttons

1. Create a screen in FoxPro that contains a date field.

2. To the right of the date field, place a button set of three buttons, and

   label the buttons +, -, and C. Adjust the size of the button set by
   clicking the lower-right corner of the set and dragging it up and to the
   left until it becomes as small as possible. You may want to choose a
   smaller font size as well. In this example, the name of the date field
   is m.lddate and the name of the button set is m.lnspinner.

3. Place the following code in the WHEN for the m.lnspinner button set:

   IF EMPTY(m.lddate)
      SHOW GET m.lnspinner, 3 PROMPT "T"
   ELSE
      SHOW GET m.lnspinner, 3 PROMPT "C"
   ENDIF

   This adjusts the prompt for the third push button. When the date field
   is empty, the prompt for the third push button will be T, otherwise it
   will remain as C.

4. Place the following code in the VALID for the m.lnspinner button set :

   DO CASE
      CASE m.lnspinner = 1  && clicked + button
         IF EMPTY(m.lddate)
            m.lddate = DATE()
         ELSE
            m.lddate = m.lddate + 1
         ENDIF
         SHOW GET m.lddate
      CASE m.lnspinner = 2  && clicked - button
         IF EMPTY(m.lddate)
            m.lddate = DATE()
         ELSE
            m.lddate = m.lddate - 1
         ENDIF
         SHOW GET m.lddate
      CASE m.lnspinner = 3  && clicked C or T button
         IF EMPTY(m.lddate)
            m.lddate = DATE()
         ELSE
            m.lddate = {}
         ENDIF
         SHOW GET m.lddate
   ENDCASE

   When the first button (+) is clicked, the date is increased by one day.
   When the second button (-) is clicked, the date is decreased by one day.
   In either case, if the date field is empty, it is set to the current
   system date. When the third button (C or T) is clicked, if the date
   field is empty, it is set to the current system date, otherwise it is
   set to an empty date value.

5. Save the screen, and generate the screen program. When you run the

   program you will now have buttons that act like a Spinner control for
   your date field.

Additional reference words: 2.50 2.50a 2.50b 2.60 2.60a date spinner FoxWin KBCategory: kbprg kbcode KBSubcategory: FxprgGeneral

Last Reviewed: September 26, 1995