LISTOF is one of the allowed types for a property. It is used with the PROPERTY keyword to specify that the property references a list of other definitions.

For example, a Class contains a property called Attributes, which is a list of class attributes. Class attribute is a definition type in of itself, which has its own set of properties. Contrast this to the property of a class called Access Type, which is a list of simple textual choices, such as Public, Private, Protected, and so on. (The LIST command is used to define this simple text list; see LIST.) Also contrast with ONEOF, which specifies that a property references exactly one other definition. An example is that a Class contains a property called Package, which specifies the one package the class resides in; Package is a definition in of itself.

The ASGRID keyword is often used with LISTOF: ASGRID presents the list of definitions in a grid; if it is not used, the definitions are listed in a default list structure.

LISTOF is sometimes used with the ZOOMABLE and also COMPLETE.

For a LISTOF property, the LENGTH keyword by default is set to 1200. LENGTH specifies how many characters the user can enter in the property field; in this case, the total number of characters of the names of definitions that can fit into the list.