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Q162546: FIX: ComboBox and ListBox Data Moves when Using Slide Control

Article: Q162546
Product(s): Microsoft FoxPro
Version(s): 5.0 5.0a
Operating System(s): 
Keyword(s): kbvfp kbvfp500aBUG kbvfp500bugkbbuglist
Last Modified: 23-MAR-2000

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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
========

Using the Slide control on the scroll bar of a dropped-down combo box or a list
box causes the data in the combo box or list box to jump around erratically.

CAUSE
=====

Setting the order on the table that is used as the RowSource property for the
combo box or list box causes this behavior.

RESOLUTION
==========

One workaround is to use an ARRAY as the RowSourceType property of the combo box
or list box.

Another workaround is to use a SQL - STATEMENT as the RowSourceType. However, if
the ORDER clause is used, it may be necessary to force Visual FoxPro to create
an actual temporary cursor on disk of the query results. This can be done by
adding a non-existing column to the resulting cursor as in the following
example:

     SELECT <desired_field>,.F. FROM <table_name> ;
        ORDER BY <desired_field> INTO CURSOR temp

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. This has been corrected in Visual FoxPro 6.0.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Paste the following lines into a program and run it to create the necessary
  table:

        CREATE TABLE xpop (cnum c(10))
        FOR i = 1 TO 5000
          APPEND BLANK
          REPLACE cnum WITH STR(i)
        ENDFOR
        INDEX ON cnum TAG cnum

  NOTE: Any table can be used but this makes it easier to see.

2. Create a form.

3. Add the table created above to the DataEnvironment (DE) of the form.

4. Right-click the table in the DE to bring up the Shortcut menu. Click
  Properties.

5. Set the Order property of the Cursor to the index tag created above.

6. Add a ComboBox or ListBox control to the form. Set the following properties:

        RowsourceType = 6 - Fields
        Rowsource     = "xpop.cnum"

7. Run the form.

8. Drop-down the combo box.

9. Drag the Slider control to some where in the middle of the scroll bar.

10. Click the left mouse button on the Slider control and then let up, note the
  contents of the drop-down jump to another place in the list and back.

11. Click the left mouse button and hold it, drag the Slider control to another
  location in the list and release. Notice that the data jumps to some other
  location.

REFERENCES
==========

For more information about forcing SQL-SELECT to create a temporary file, please
see the following article(s) in the Microsoft Knowledge Base:

  Q109584 How To Force SELECT-SQL to Create Temp File for Cursor

Additional query words: kbvfp600fix

======================================================================
Keywords          : kbvfp kbvfp500aBUG kbvfp500bug kbbuglist
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP500a
Version           : 5.0 5.0a
Issue type        : kbbug
Solution Type     : kbfix

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