IsFalse Operator (Visual Basic)
Determines whether an expression is False
.
You cannot call IsFalse
explicitly in your code, but the Visual Basic compiler can use it to generate code from AndAlso
clauses. If you define a class or structure and then use a variable of that type in an AndAlso
clause, you must define IsFalse
on that class or structure.
The compiler considers the IsFalse
and IsTrue
operators as a matched pair. This means that if you define one of them, you must also define the other one.
Note
The IsFalse
operator can be overloaded, which means that a class or structure can redefine its behavior when its operand has the type of that class or structure. If your code uses this operator on such a class or structure, be sure you understand its redefined behavior. For more information, see Operator Procedures.
Example
The following code example defines the outline of a structure that includes definitions for the IsFalse
and IsTrue
operators.
Public Structure p
Dim a As Double
Public Shared Operator IsFalse(ByVal w As p) As Boolean
Dim b As Boolean
' Insert code to calculate IsFalse of w.
Return b
End Operator
Public Shared Operator IsTrue(ByVal w As p) As Boolean
Dim b As Boolean
' Insert code to calculate IsTrue of w.
Return b
End Operator
End Structure