Set Collection (PRIM_SCOL)
Unordered collection of components that cannot contain duplicates
Ancestors - Collection (PRIM_COLL)Object (PRIM_OBJT)
Details
Set collections provide an ordered collection of components that does not allow duplicates.
The features of the Set 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.
Set collections and Array collections are very similar in nature.
Examples
Defining a Set collection. This collection stores instances of a user defined customer data object.
Define_Com Class(#Prim_Scol<#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
Name |
Description |
AllowsDuplicates indicates whether the collection allows duplicates Inherited from Collection (PRIM_COLL) |
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The class of object to be collected |
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ComponentClassName is the name of the component's class. Inherited from Object (PRIM_OBJT) |
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ComponentMembers provides access to all the member components of this component Inherited from Object (PRIM_OBJT) |
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ComponentPatternName is used to qualify the class of the component. Inherited from Object (PRIM_OBJT) |
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Generic space allowing a value to be stored for the instance Inherited from Object (PRIM_OBJT) |
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ComponentType gives you access to the type information about the component Inherited from Object (PRIM_OBJT) |
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ComponentTypeName is the fully qualified name of the component's class. Inherited from Object (PRIM_OBJT) |
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IsEmpty indicates whether the collection contains any items. Inherited from Collection (PRIM_COLL) |
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IsOrdered indicates whether the collection is ordered. Inherited from Collection (PRIM_COLL) |
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Provides access to a particular item in a collection |
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ItemCount is the number of items in a collection Inherited from Collection (PRIM_COLL) |
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Name identifies the component Inherited from Object (PRIM_OBJT) |
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Owner owns this component Inherited from Object (PRIM_OBJT) |
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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 is signalled when an instance of a component is created Inherited from Object (PRIM_OBJT) |
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DestroyInstance is signalled when an instance of a component is about to be destroyed Inherited from Object (PRIM_OBJT) |
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Hash is triggered when an integer value needs to be determined to organize the collection Subject, Hash |
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Fired whenever the collection needs to compare two items Object, Subject, Equal |
Methods
Name |
Description |
CalculateHash calculates a hash value Inherited from Collection (PRIM_COLL) Result, Value |
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Does the supplied instance exist in the collection? Result, Object |
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CreateAccessor creates an accessor component that provides read-only access to the collection Result |
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CreateIterator method creates an iterator component that enables iteration through the collection Result |
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Find method returns a reference to a item in a collection Result, Object |
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Insert adds an item to a collection Result, Item |
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Remove method removes an item Result, Object |
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RemoveAll removes all items in the collection |