FIX: ComboBox and ListBox Data Moves when Using Slide Control

• Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a

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 FxprgGeneral
Version : 5.0 5.0a
Platform : WINDOWS
Issue type : kbbug