fx:Null markup extension

The fx:Null markup extension specifies the null value.

The text "null" has no intrinsic null value in an ordinary assignment. In particular, assigning value="null" to an Object property produces the string "null"; use {fx:Null} when the assigned value must be null.

As a method argument, the unquoted keyword null is the null literal. Quote it as 'null' to pass a string, or qualify it as a path such as :element.null to refer to a property named null.

Usage

<!-- Using the fx:Null markup extension -->
<Button graphic="{fx:Null}"/>

<!-- The Object-valued property receives null, not the string "null" -->
<Button userData="{fx:Null}"/>

<!-- Null and string literals as method arguments -->
<Button text="$String.format('%s / %s', null, 'null')"/>