Dictionary Collection (PRIM_DCOL)

Unordered collection of component pairs typically used to associate objects with each other

Ancestors - Collection (PRIM_COLL)Object (PRIM_OBJT)

Details

Dictionary collections are an unordered sequence of key-value component pairs with no duplicates of the key.
 
A dictionary collection is keyed by an instance of an object type, giving each collection item a unique identifier.

Examples

Defining a dictionary collection. This collection stores instances of layout items identified by a control.
Define_Com Class(#Prim_dcol<#Prim_tblo #Prim_ctrl>) Name(#LayoutItems)
Collection items can be created by assigning them to an existing reference or creating a new one as below.
#LayoutItems<#Button1> <= (*New #Prim_TBLO)
Collection items can be accessed using any object type that inherits from the class specified as the key.
#LayoutItems<#Button1>.Manage <= #Button1
All collection items can be addressed as follows. Here, all the layout items are being assigned a parent.
#LayoutItems<>.Parent <= #LayoutManager
The FOR command can also be used to iterate over the collection contents. The items will be returned in the order of the key value, which in this case is effectively the memory address of the key.
For each(#LayoutItem) in (#Layoutitems)
   ...
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, the closing event on a collection of forms is monitored and an event recorded.
Evtroutine Handling(#Forms<>.Closing) Com_Sender(#Sender)
 
   #Com_owner.AddEvent(("&1 closed").Substitute(#Sender.Caption))
 
Endroutine

Properties

Name Description
AllowsDuplicates AllowsDuplicates indicates whether the collection allows duplicates Inherited from Collection (PRIM_COLL)
Collects The class of object to be collected
ComponentClassName ComponentClassName is the name of the component's class. Inherited from Object (PRIM_OBJT)
ComponentMembers ComponentMembers provides access to all the member components of this component Inherited from Object (PRIM_OBJT)
ComponentPatternName ComponentPatternName is used to qualify the class of the component. Inherited from Object (PRIM_OBJT)
ComponentTag Generic space allowing a value to be stored for the instance Inherited from Object (PRIM_OBJT)
ComponentType ComponentType gives you access to the type information about the component Inherited from Object (PRIM_OBJT)
ComponentTypeName ComponentTypeName is the fully qualified name of the component's class. Inherited from Object (PRIM_OBJT)
IsEmpty IsEmpty indicates whether the collection contains any items. Inherited from Collection (PRIM_COLL)
IsOrdered IsOrdered indicates whether the collection is ordered. Inherited from Collection (PRIM_COLL)
Item Provides access to a particular item in a collection
ItemCount ItemCount is the number of items in a collection Inherited from Collection (PRIM_COLL)
KeyedBy KeyedBy specifies the field used to identify a form instance
KeyOf KeyOf returns the key of an item in a collection
Name Name identifies the component Inherited from Object (PRIM_OBJT)
Owner Owner owns this component Inherited from Object (PRIM_OBJT)
Parent The component instance to which this instance is attached. The visual container for a control or the collector of a set of child instances Inherited from Object (PRIM_OBJT)

Events

Name Description
CreateInstance CreateInstance is signalled when an instance of a component is created Inherited from Object (PRIM_OBJT)
DestroyInstance DestroyInstance is signalled when an instance of a component is about to be destroyed Inherited from Object (PRIM_OBJT)
Hash Hash is triggered when an integer value needs to be determined to organize the collection
Subject, Hash
IsEqual Fired whenever the collection needs to compare two items
Object, Subject, Equal

Methods

Name Description
CalculateHash CalculateHash calculates a hash value Inherited from Collection (PRIM_COLL)
Result, Value
Contains Does the supplied instance exist in the collection?
Result, Key
ContainsItem ContainsItem looks for an item in a collection
Result, Item
CreateAccessor CreateAccessor creates an accessor component that provides read-only access to the collection
Result
CreateIterator CreateIterator method creates an iterator component that enables iteration through the collection
Result
Find Find method returns a reference to a item in a collection
Result, Key
Insert Insert adds an item to a collection
Result, Item, Key
Remove Remove method removes an item
Result, Key
RemoveAll RemoveAll removes all items in the collection

See also

All Component Classes

Technical Reference

LANSA Version 15, April 2020