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Q165920: PRB: Correct Usage of "&" and "AND" in Visual Basic

Article: Q165920
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,5.0,6.0
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SYMPTOMS
========

This code works in Visual Basic 3.0:

       If Form1.Text1.Text = "" & Form1.Text2.Text = "" Then...

but fails in Visual Basic 4.0 and later with a "type mismatch" error.

The correct syntax for this statement is:

       If Form1.Text1.Text = "" And Form1.Text2.Text = "" Then...

Confusing the concatenation operator "&" with the logical operator "AND" will
result in "type mismatch errors."

CAUSE
=====

This is a result of the data type of (Boolean) being added to Visual Basic 4.0
and later.

RESOLUTION
==========

When performing logical comparisons between operands, be sure to use the logical
operators (AND, OR) as opposed to the concatenation operator "&" in Visual
Basic 4.0.

STATUS
======

This is by design.

MORE INFORMATION
================

In Visual Basic 3.0, a logical comparison between operands would result in
either a 1 or a 0 being returned. With Visual Basic 4.0 and later, a logical
data type has been added so that a logical comparison between two operands will
result in either a "TRUE" or "FALSE" value being returned. Attempting to use the
concatenation operator "&" can not be performed in Visual Basic 4.0 and
later on these logical data types. Therefore, an error is raised.

Additional query words: kbVBp kbdsd kbDSupport kbVBA kbVBp400 kbVBp500 kbVBp600

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600 kbVB400Search kbVB400 kbVB16bitSearch
Version           : WINDOWS:4.0,5.0,6.0
Issue type        : kbprb

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