Article: Q156925
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,6.0
Operating System(s):
Keyword(s): kbvfp500 kbvfp600
Last Modified: 14-DEC-1999
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The information in this article applies to:
- Microsoft Visual FoxPro for Windows, versions 5.0, 6.0
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SYMPTOMS
========
In Visual FoxPro 5.0, when assigning a null value to a property in the
Properties window, you need to use .NULL. instead of NULL. The values are not
interchangeable when used in a property in the Properties window.
CAUSE
=====
In the Properties window, you do not have to enter quotes to enter a string. The
text NULL entered without the quotes is interpreted as the string 'NULL' instead
of the actual .NULL. value.
WORKAROUND
==========
You need to enter the string as .NULL. in the Properties window.
STATUS
======
This behavior is by design.
MORE INFORMATION
================
At times, you may wonder why you can enter the following in the Command window
and get the expected result:
X=NULL
?ISNULL(X) <-- .T. is return
However, ISNULL() evaluates as .F. instead of .T. when a NULL value, without the
period on both ends, is assigned to a property in the Properties window.
Steps to Reproduce Behavior
---------------------------
1. Create a new form.
2. Create a new property named NullProperty.
3. In the Properties window, assign NULL to NullProperty property (that is,
without periods before and after NULL).
4. Put the following in the form Init:
?ISNULL(THIS.NullProperty)
5. Run the form.
Visual FoxPro returns .F.
Additional query words: kbdse VFoxWin
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Keywords : kbvfp500 kbvfp600
Technology : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600
Version : WINDOWS:5.0,6.0
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