Q167186: PRB: SET CENTURY ROLLOVER Ignores Setting of SET CENTURY OFF
Article: Q167186
Product(s): Microsoft FoxPro
Version(s): 5.0,5.0a
Operating System(s):
Keyword(s): kbProgramming kbYear2000 kbvfp kbvfp500 kbvfp500a
Last Modified: 14-AUG-2001
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The information in this article applies to:
- Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a
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SYMPTOMS
========
When using the ROLLOVER parameter of SET CENTURY, the SET CENTURY OFF setting is
ignored. This results in a date display consisting of either two digits or four
digits for the year portion of the date.
RESOLUTION
==========
The reason for the display of the year in either a two- or four-digit format is
to differentiate which century the date belongs to.
It is possible to create a custom display format, which presents the date in the
MM/DD/YY format along with another field to display which century.
The following program demonstrates a sample method to do this.
Step-by-Step Procedures
-----------------------
1. Save the following code as Daterev.prg:
*** Begin code ***
ON KEY LABEL f2 CLEAR EVENTS
ON KEY LABEL f3 DO refresh
SET CENTURY to 19 ROLLOVER 60
SET CENTURY off
dateform=CREATEOBJECT('form')
WITH dateform
.width=300
.height=65
.ADDOBJECT('text1','textbox')
WITH .text1
.format='K'
.inputmask='99/99/99'
.left=1
.top=10
.width=60
.value=DTOC(date())
.visible=.t.
ENDWITH && text1
.ADDOBJECT('label1','label')
WITH .label1
.top=50
.left=90
.width=120
.fontbold=.t.
.caption="Press <F2> to exit form"
.visible=.t.
ENDWITH && label1
.ADDOBJECT('label2','label')
WITH .label2
.caption="Year of date shown is "+ ;
ALLTRIM(STR(YEAR(CTOD(dateform.text1.value))))
.top=32
.left=10
.width=160
.fontbold=.t.
.visible=.t.
ENDWITH && label2
.ADDOBJECT('label3','label')
WITH .label3
.caption='Press <f3> to refresh after entering new date'
.top=10
.left=65
.width=250
.fontbold=.t.
.visible=.t.
ENDWITH && label3
.show
ENDWITH && dateform
READ EVENTS
ON KEY LABEL f2
ON KEY LABEL f3
PROCEDURE refresh
dateform.label2.caption="Year of date shown is: "+ ;
ALLTRIM(STR(YEAR(CTOD(dateform.text1.value))))
dateform.refresh
RETURN
*** End code ***
2. Run the program, and note that the four-digit display of the date shown is
shown below the text box.
3. Enter a valid date for the 21st century, such as "02/12/55."
4. Press the F3 key to refresh the display, and note that in the line below the
text box, the year is shown as "2055."
STATUS
======
This behavior is by design.
MORE INFORMATION
================
The ROLLOVER clause of SET CENTURY command permits ease of entering dates that
may cross century boundaries. For example:
SET CENTURY to 19 ROLLOVER 60
This means that when a two-digit value for a year "60" and greater falls within
the 21st century, two-digit values less than 60 fall into the 20th century.
Using the information above, "02/15/97" is deemed the year "1997." And "02/15/55"
is interpreted as the year 2055.
To better understand the implications of the ROLLOVER parameter, the following
program demonstrates its effect on how dates are displayed.
Steps to Reproduce Behavior
---------------------------
1. Save the following code as Formdate.prg:
*** Begin code ***
ON KEY LABEL f2 CLEAR EVENTS
SET CENTURY to 19 ROLLOVER 60
SET CENTURY off
dateform=CREATEOBJECT('form')
WITH dateform
.width=120
.height=65
.ADDOBJECT('text1','textbox')
WITH .text1
.format='K'
.left=35
.top=10
.width=75
.value=date()
.visible=.t.
ENDWITH && text1
.ADDOBJECT('label1','label')
WITH .label1
.top=35
.left=1
.width=120
.fontbold=.t.
.caption="Press <F2> to exit form"
.visible=.t.
ENDWITH && label1
.show
ENDWITH && dateform
READ EVENTS
ON KEY LABEL f2
*** End code ***
2. Run the program, and note that the current date appears with two digits for
year.
3. In the text box, enter a date with a year less than 60, such as 01/10/56. As
soon the "56" is entered, the year is displayed as "2056."
4. Enter a date with a year greater than 60, such as 12/01/99, and note that the
date is shown with only the last two digits of the year omitting the century.
REFERENCES
==========
For more information about SET CENTURY, search for CENTURY in the Visual FoxPro
Help file.
Additional query words:
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Keywords : kbProgramming kbYear2000 kbvfp kbvfp500 kbvfp500a
Technology : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP500a
Version : :5.0,5.0a
Issue type : kbprb
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