Sequential collection of objects accessible via an index

Ancestors - Collection (PRIM_COLL) Object (PRIM_OBJT)

Details

List collections provide an ordered collection of components.
 
The features of the list component are positional in nature, in reference to a given index or to the beginning or end of the list. Indexing is always relative to 1.
 
List collections and Array collections are very similar in nature, the only real difference being the way they handle memory allocation in Windows.

Examples

Defining a list collection. This collection stores instances of a user defined customer data object.

Define_Com Class(#Prim_Lcol<#Customer>) Name(#Customers)

Collection items can be created by assigning them to an existing reference or creating a new one as below.

#Customers.Insert((*New #Customer))

Collection items can be accessed by their position in the collection.

#Customers<123>.CustomerName := #CustomerName

All collection items can be addressed as follows. Here, all the customers in the collection are having a property value incremented.

#Customers<>.CreditLimit += 1000

The FOR command can also be used to iterate over the collection contents. The items will be returned in the order they are stored in the collection.

For each(#Customer) in (#Customers)
   ...
Endfor

To monitor for an event from any instance in the collection, <> can be appended to an EVTROUTINE. The COM_SENDER parameter will provide access to the instance firing the event.
 
In this example, a changed event on the customer instances is monitored.

Evtroutine Handling(#Customers<>.Changed) Com_Sender(#Sender)
 
   #Com_owner.AddEvent(("&1 changed").Substitute(#Sender.CustomerName))
 
Endroutine

Properties

Events

Methods

See also

All Component Classes

Technical Reference

Febuary 18 V14SP2