Knowledge Base

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

Article ID: 165920

Article Last Modified on 7/14/2004

APPLIES TO

This article was previously published under Q165920

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

Keywords: kbprb KB165920


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