PRB: Grid Not Refreshing Displaying a Cursor From Query

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

SYMPTOMS

If a Grid's RecordSource property is set to a cursor and that cursor is updated at run time by using a "SQL Select Into Cursor <CursorName>" command, the grid does not display any data even if you Refresh it by using the ThisForm.Refresh or ThisForm.<GridName>.Refresh command.

CAUSE

When you execute a SQL Select statement into the same cursor specified in the grid's RecordSource property, the original cursor has to be destroyed before the new cursor can be created. When this happens, the grid columns and the RecordSource are also cleared and then re-created. The grid's record source is set to the new cursor, and the grid automatically creates columns. The new grid is working from scratch, so it does not load the data from the cursor.

RESOLUTION

To refresh the grid in this situation, set the Grid's RecordSource property to itself as in this example:

    thisform.grid1.recordsource=thisform.grid1.recordsource

STATUS

This behavior is by design.

MORE INFORMATION

For more information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q140653
   TITLE     : PRB: Cursor-Based Grid Goes Blank If SQL SELECT Resets
               Cursor

Steps to Reproduce Behavior

1. Create a form, and add the CUSTOMER.DBF table (in the \VFP\SAMPLES\DATA directory) to the Data Environment.

2. Place the following code in the Load event of the form:

   CREATE CURSOR Compdisp (company c(40),city c(15),country c(15))

3. Place the following code in the Destroy event of the form:

   SELECT Compdisp USE

4. Create a grid on the form, and give the grid the following property settings:

   ColumnCount=3 RecordSourceType=Alias RecordSource=Compdisp

5. Add a text box to the form.

6. Add a command button with the following code in its Click event:

   SELECT company,city,country;

         FROM customer;
         WHERE customer.country=thisform.text1.value;
         INTO CURSOR Compdisp
   

   THISFORM.GRID1.REFRESH

7. Run the Form. Type "France" in the text box, and then click the command button.

To have the grid display the data correctly, place the following command as the last line of code for the Click event of the command button:

   ThisForm.Grid1.RecordSource =ThisForm.Grid1.RecordSource