BUG: VFP CDX with EMPTY Function Is Not Recognized in VB

ID: Q175691

The information in this article applies to:

Microsoft Visual Basic Professional and Enterprise Editions for Windows, versions 5.0, 6.0

SYMPTOMS

FoxPro indexes that contain the function EMPTY or ISBLANK will not be recognized in Visual Basic. Indexes with this function are recognized by Visual Basic 4.0. The following error will be generated under NT:

   An application error has occurred
   and an application error log is being generated.

   VB5.exe
   Exception Access Violation (0xc0000005),Address .........

Visual Basic is terminated by this error.

In Windows 95 and Windows 98, no error is returned because the index is not seen.

RESOLUTION

Compare field to " " instead of using EMPTY. The same results are achieved.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a Visual Basic project and choose DAO 3.5 under project

   references.

2 In FoxPro 2.5, use the customer table and set up some indexes on cno,

  state and ono. The CDX file with the same name as the table file will
  contain the indexes.

3. Place 2 CommandButtons on the form, and paste in the following code:

      Option Explicit

      Dim FoxDataDB As Database
      Dim RS As Recordset
      Dim myidx As Index

      Private Sub Command1_Click()
        RS.Close
        FoxDataDB.Close
        Set RS = Nothing
        Set FoxDataDB = Nothing
        Unload Me
      End Sub

      Private Sub Command2_Click()
         For Each myidx In FoxDataDB.TableDefs("customer").Indexes
            Debug.Print myidx.Name
            RS.Index = myidx.Name
         Next
      End Sub

      Private Sub Form_Load()

      Set FoxDataDB = Workspaces(0).OpenDatabase( _
                         "d:\fpw26\tutorial", _
                         False, False, "FoxPro 2.5;")
         Set RS = FoxDataDB.OpenRecordset("customer", dbOpenTable)

      End Sub

4. Run the code above and note that the index names are printed.

5. Delete some phone numbers from the database above and add the following

   index by choosing Database Setup from the menu in FoxPro:

      IIF(EMPTY(phone), state, phone)

6. Run the code above and note that you get the error above under NT. Under

   Windows 95 and Windows 98, the index will not be recognized.

7. Remove the phone index, and the program will run successfully if the

   index has not become corrupted.

Additional query words: Dr. Watson function complex immediate inline kbVBp500bug kbVBp kbWinOS98 kbDSupport kbdse kbVBp600 kbDSupport kbVBp kbDAO350 kbVFP250

Platform          : WINDOWS
Hardware          : x86
Issue type        : kbbug

Last Reviewed: August 7, 1998