HOWTO: Refresh a Graph

• Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0

SUMMARY

Previous versions of FoxPro could call procedures (refreshgrph, updategrph) that were built into the Graph Wizard to redraw a chart to reflect changes in data. While this functionality was never officially supported, the information was made available to customers and many developers used it.

This article gives example code for the equivalent functionality using Visual FoxPro and the new Graph Wizard. Of course, it is only intended as an example, your tables and so will be different.

MORE INFORMATION

Assumptions

• A form exists and that there is an olebound control on the form with its ControlSource property set to a table that has charts in a General field.
• The Spcgrph table is opened exclusively.
• The tables used are Phonz.dbf which contains the data and Spcgrph.dbf which has a general field called olegraph that contains the chart.

Using the Code

** Select the work area and turn off the console
SELECT PHONZ
SET CONSOLE OFF
SELECT email,  avg_time, FROM PHONZ INTO CURSOR SPCRES

**  Now the data is in the cursor SPCRES. The table with the graph in it
**  needs to have the current record deleted. The following code
**  adds the updated chart in a new record. The operation seems to
**  confuse the olebound control, so you should lock the screen, so
**  you won't see it. Then set the controlsource of the olebound control
**  to null for the duration.
**
**  Note that the wizard does not just modify the chart that you are
**  on, it appends a new record with a new chart. If you don't want
**  your table to grow every time that you do this, you must delete
**  the current record.
**
**  The spcgrph table must be packed after deletion, so it must
**  be opened exclusivly. Because the Wizard leaves spcgrph opened
**  non-exclusivly, it needs to be closed and re-opened.

select spcgrph
delete
pack
use
thisform.lockscreen = .T.

thisform.oleboundcontrol1.controlsource = ""

**  Load the New chart

    SELECT SPCRES
    DO (_GENGRAPH) WITH "AUTOGRAPH", 4, 1, "Test1",,,,"spcgrph",.T.

** NOTE: If you are using Visual FoxPro 6.0, make sure to add a .dbf
** extension to "spcgrph" or the data is written to a .scx file.
** After using this wizard, the graph table (spcgrph) is open, but it
** is not open exclusively. Note that if you had more than one chart
** in the table, you would have to do some fancy shuffling at this point
** to make sure that you were on the right record. (the one that you want
** to show in the form.

select spcgrph
use
use spcgrph.dbf in 0 exclusive

**  Close the cursor and go back where you came from

    SELECT SPCRES
    USE
    SELECT PHONZ

    thisform.oleboundcontrol1.controlsource = "spcgrph.olegraph"
    thisform.lockscreen = .F.

** Refresh the Form
<BR/><BR/>
THISFORM.REFRESH
THISFORM.OLEBOUNDCONTROL1.REFRESH

******************* End Of Code ****************************** 

Additional query words:

Keywords : kbcode kbVFp300 kbVFp300b kbVFp500
Version : WINDOWS:3.0,3.0b,5.0
Platform : WINDOWS
Issue type : kbhowto