Sorted Dictionary Collection (PRIM_SDCO)
Unordered collection of unique 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. When an item is added to the collection, the Compare event is fired as often as required to allow a user defined sort to be evaulated.
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 |
|---|---|
| Compare | Compare is triggered when two key components need to be compared
Object, Subject, Result |
| 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) |
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
LANSA Version 15, April 2020