Microsoft KB Archive/208579

= ACC2000: Yes/No Field Not Evaluating "-1" or "0" in Comparisons =

Article ID: 208579

Article Last Modified on 7/15/2004

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APPLIES TO


 * Microsoft Access 2000 Standard Edition

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This article was previously published under Q208579



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

This article applies only to a Microsoft Access database (.mdb).



SYMPTOMS
Code written in Access Basic that uses "-1" or "0" (with the quotation marks) to compare a Yes/No field in a table or recordset does not work properly when you convert the Access Basic code to Visual Basic for Applications code. In Access version 2.0, which uses Access Basic, the numeric comparisons are evaluated as strings. In Access 7.0 and later, which use Visual Basic for Applications, the numeric comparisons are evaluated as Boolean values.



CAUSE
In Access Basic the condition If rs![yesnofield] = "-1" Then is evaluated as True, and the condition If rs![yesnofield] = "0" Then is evaluated as False.

In Visual Basic for Applications, these conditions are no longer evaluated in this manner.



RESOLUTION
In an open Access Basic or Visual Basic for Application module window, use the Find command on the Edit menu to check for instances of the strings "-1" or "0" (with the quotation marks).

Change all instances in Visual Basic for Applications where "-1" or "0" is used to compare a Yes/No field in a table or recordset as follows.

If you are using the following expression in Access Basic

IF rs![yesnofield] = "-1" Then in Visual Basic for Applications, change the code so that there are no quotation marks around the number "-1" or use the word "True" as in the following example: IF rs![yesnofield] = -1 Then

-or-

IF rs![yesnofield] = True Then If you are using the following expression in Access Basic: IF rs![yesnofield] = "0" Then in Visual Basic for Applications, change the code so that there are no quotation marks around the number "0" or use the word "False" as in the following example: IF rs![yesnofield] = 0 Then

-or-

IF rs![yesnofield] = False Then



Steps to Reproduce Behavior
 Start Microsoft Access 2.0 and open the sample database NWIND.MDB.  Open the Products form in Design view and set the OnCurrent property of the form to the following event procedure: Sub Form_Current Dim rs As Recordset Set rs = Me.RecordsetClone rs.Bookmark = Me.Bookmark

If rs![Discontinued] = "-1" Then MsgBox "This product is discontinued." End If

Set rs = Nothing

End Sub  Open the Products form in Form view and, using the record selectors, move through the records. Note that a message box appears for all discontinued products.  Start Microsoft Access 2000, and repeat steps 1 through 3. In step 2, change the first line of code that reads Sub Form_Current to read as follows: Private Sub Form_Current  Open the Products form in Form view and, using the record selectors, move through the records. Note that the message box for the discontinued products does not appear.</li></ol>

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