How To Check for Changed Record in Grid & Prompt User to Save

The information in this article applies to:

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

SUMMARY

This article shows by example how to:

• How to check to see if a record has been changed when you're using a grid to edit records in a table with Table Buffering.
• How to prompt users to update a changed record before they move to a different record.

MORE INFORMATION

If you are not familiar with Data Buffering, please see Chapter 19 in the Developer's Guide. For more information on using Forms and Controls, please see Chapters 9 and 11 in the Developer's Guide.

Step-by-Step Example

1. Create a new form. Add the Customer table (located in Samples\Data in the Visual FoxPro directory) to the form's Data Environment

2. Set the BufferMode property of the form to one of the values below:

         1 - Pessimistic
   

           -or-
   
         2 - Optimistic
   
      With either of these settings, the grid, soon to be added to the form,
      uses table buffering while any other controls, such as text boxes or
      edit boxes, uses row buffering. Alternately, the BufferModeOverride
      property of the cursor can be set to either of these values:
   
         4 - Pessimistic Table Buffering
   
           -or-
   
         5 - Optimistic Table Buffering
   
      The BufferMode property of the form can be set as desired. The code in
      this article will not work if the BufferModeOverride property of the
      cursor is set to either type of Row Buffering. This is because with Row
      Buffering on the cursor in the grid, any changes to the current record
      will be committed when moving to the next record in the grid and the
      GETFLDSTATE() function will not detect the change.
   
   

3. Add two new properties to the form, and call them nRecNum and nWhatRow. Set their Value properties to 0.

4. Add a grid to the form, and set the following properties for the grid:

   RecordSource = Customer RecordSourceType = 1 - Alias

5. Add the following code to the indicated grid events:

   Init event

          ThisForm.nRecNum = RECNO()
   

   BeforeRowColChange

          ThisForm.nRecNum = RECNO()
   

   AfterRowColChange

          lMov = .F.
          IF ThisForm.nWhatRow # This.ActiveRow
               ThisForm.nWhatRow = This.ActiveRow
               nHold= RECNO()
               GO ThisForm.nRecNum
               cChange = GetFldState(-1,'Customer')
               IF AT('2', cChange)>0
                 This.Refresh
                 lMov = .T.
                 IF MessageBox("Update Record",4)= 6
                   =TableUpdate(.T.)
                 ELSE
                   =TableRevert(.T.)
                 ENDIF
                ENDIF
                GO nHold
                IF lMov
                  This.Refresh
                  lMov =.F.
                ENDIF
              ENDIF
   
   

6. Save and run the form.