ACC: How to Test a User-Defined Filter in Filter By Form

• Microsoft Access versions 7.0, 97

SUMMARY

Moderate: Requires basic macro, coding, and interoperability skills.

This article shows you how to test the validity of a user-defined filter when using the Filter By Form feature of Microsoft Access. The sample procedure demonstrates some of the validation techniques that you can use to ensure that the filter that you apply to the form returns records.

This article assumes that you are familiar with Visual Basic for Applications and with creating Microsoft Access applications using the programming tools provided with Microsoft Access. For more information about Visual Basic for Applications, please refer to your version of the "Building Applications with Microsoft Access" manual.

MORE INFORMATION

In this example, if the filter that you apply does not return any records, a message appears, and you return to the Filter By Form screen to retry the filter:

1. Open the sample database Northwind.mdb.



2. Open the Employees form in Design view.



3. Set the OnApplyFilter property to the following event procedure:




       Private Sub Form_ApplyFilter(Cancel As Integer, ApplyType As _
          Integer)
          Me.TimerInterval = 100
       End Sub 

4. Set the OnTimer property to the following event procedure:




       Private Sub Form_Timer()
          Dim strfilter As String
          Me.TimerInterval = 0
          If IsNull(Me.Filter) Then Exit Sub
          strfilter = Me.Filter
          If Me.RecordsetClone.RecordCount = 0 Then
              MsgBox "The selected filter:" & Chr(13) & _
              strfilter & Chr(13) & _
              "returns no records. Try a less restrictive search."
              ' Form, Records, Filter, Filter By Form.
              DoCmd.DoMenuItem 0, 5, 0, 0, acMenuVer70
          End If
       End Sub 

5. Save and open the form in Form view.



6. On the Records menu, point to Filter, and then click Filter By Form.



7. In the First Name field, select Laura.



8. On the Filter menu, click Apply Filter/Sort. Note that the record for Laura Callahan is returned.



9. On the Records menu, point to Filter, and then click Filter By Form.



10. In the First Name field, type "Test" (without the quotation marks).



11. On the Filter menu, click Apply Filter/Sort.



12. Note that the following message appears, indicating the filter does not return records:




The selected filter:
((Employees.FirstName="Test"))
returns no records. Try a less restrictive search.

REFERENCES

For more information about OnFilter and OnApplyFilter, type "Filters and OnApplyFilter," in the Office Assistant, click Search, and then click to view the appropriate topic.

Additional query words: Validate FormFilter Count Query

Keywords : kbusage
Version : WINDOWS:7.0,97
Platform : WINDOWS
Issue type : kbhowto