HasValue Procedure

Determines whether an Optional contains a value of the underlying type, or whether it is none.

Declaration

function HasValue(this as Optional T) as Boolean

Boolean — If this contains a value (of type T), then HasValue returns true. Otherwise, it returns false.

This example shows how HasValue responds to changes in an Optional Number variable.

Code

dim x as Optional Number

if not HasValue(x) then print "HasValue is initially false"

let x = 123

if HasValue(x) then print "HasValue is now true"

let x = none

if not HasValue(x) then Print "HasValue is false again"

Output

HasValue is initially false

HasValue is now true

HasValue is false again