Add an undefined parameter to keyword.

Undefined can mean different things for different applications, though the most common is "use default value". Before using the undefined parameter, be sure that the model/tool that uses the PFS file supports handling undefined parameters.

Restrictions: The function is only valid within the scope of a keyword.

void AddUndefinedPar()

Sub AddUndefinedPar

void AddUndefinedPar()

abstract AddUndefinedPar : unit -> unit