CBool Function

Converts an expression or a set of expressions into a boolean. An expression is composed of strings, numbers and operators. Comparison, logical or mathematical operators are allowed inside expressions.


  CBool (expression As Variant) As Boolean

expression can be a number or a set of combined expressions.

Return value:



expression: A logical expression, a mathematical formula, a numeric expression or a set of expressions combined with operators. During expression evaluation logical operators take preceedence over comparison operators, which in turn take preceedence over mathematical operators.

The expression can be a number or mathematical formula. When equals to 0, False is returned, otherwise True is returned.

Multiple expressions such as expr1 [[{operator] expr2]..] can be combined. expr1 and expr2 can be any string or numeric expressions that you want to evaluate. CBool combines the expressions and returns either True or False. operator can be a mathematical operator, logical operator or comparison operator.

Error codes:

5 無効なプロシージャー呼び出しです


In the following examples, the CBool function evaluates a logical expression, a mathematical formula and the value that is returned by the Instr function. The function checks if the character "a" is found in the sentence that was entered by the user.

Sub ExampleCBool
    Print CBool( 1>2 Xor 44 ) ' computes to True
    Print CBool( expression := 15 /2 -7.5 ) ' displays False as expression equals 0
    txt = InputBox("Please enter a short sentence:")
    ' Proof if the character "a" appears in the sentence.
    REM 通常こうした判定には下記のような IF 文を使います。
    ' If Instr(Input, "a")<>0 Then...
    REM ここではその代わりに CBool 関数を使って判定をしています。
    If CBool(Instr(txt, "a")) Then
        MsgBox "The character »a« appears in the sentence you entered!"
End Sub