Collection

Qualified name: delphifmx.Collection

class Collection

Bases: Persistent

TCollection is a container for TCollectionItem objects. Each TCollection holds a group of TCollectionItem descendants. TCollection maintains an index of the collection items in its Items array. The Count property contains the number of items in the collection. Use the Add and Delete methods to add items to the collection and delete items from the collection. Objects descended from TCollection can contain objects descended from TCollectionItem. Thus, for each TCollection descendant, there is a corresponding TCollectionItem descendant. The following table lists some typical descendants of TCollection with the corresponding TCollectionItem descendant and the component that uses each pair:

TCollection descendant

TCollectionItem descendant

Component

TBitmapLinks

TBitmapLink

TCustomStyleObject

TAggregates

TAggregate

TClientDataSet

TCookieCollection

TCookie

TWebResponse

TCoolBands

TCoolBand

TCoolBar

TDBGridColumns

TColumn

TDBGrid

TDependencies

TDependency

TService

THeaderSections

THeaderSection

THeaderControl

TListColumns

TListColumn

TListView

TParams

TParam

many datasets

TStatusPanels

TStatusPanel

TStatusBar

The controls that use TCollection and TCollectionItem descendants have a published property that holds a collection. (For example, the Panels property of TStatusBar holds a TStatusPanels.) A standard property editor, referred to generically as the Collection editor, can be invoked from the Object Inspector to edit the items in the collection.

Note: When writing a TCollection descendant that is used by another control, be sure to override the protected GetOwner method of the collection so that the descendant class instances can appear in the Object Inspector. Note: TCollection has the TOwnedCollection descendant that maintains information about its owner. TOwnedCollection implements the GetOwner method. Therefore, classes derived from TOwnedCollection do not need to add anything in order to appear in the Object Inspector.

Methods

Add	Adds a collection item to the collection
Assign	Copies the contents of the Source collection to the current object.
BeginUpdate	Suspends screen repainting.
Clear	Clears all collection items
ClearAndResetID	Embarcadero Technologies does not currently have any additional information.
Delete	Deletes a single item from the collection.
EndUpdate	Re-enables screen repainting.
FindItemID	Returns the item with the specified ID.
GetEnumerator	Returns a TCollection enumerator.
GetNamePath	Returns a string used by the Object Inspector.
Insert	Inserts a new collection item to the collection at the Index position
Sort	Embarcadero Technologies does not currently have any additional information.

Attributes

Capacity	Provides access to the internal TList.Capacity property.
ClassName	Returns the TObject.ClassName
Count	Returns the count of collection items
IsEmpty	bool:
ItemClass	Indicates the class to which the collection's items belong.
Items	Returns an iterator over the collection items
Owner	Returns the Owner of the collection

Add()

Adds a collection item to the collection

Assign(Source: Persistent) → None

Copies the contents of the Source collection to the current object. Use Assign to copy the contents of one TCollection instance to another. The Assign method deletes all items from the destination collection (the object where it is executed), then adds a copy of each item in the source collection’s Items array. Source is another object (typically another collection) that contains the items that replace this collection’s items.

BeginUpdate()

Suspends screen repainting.

Capacity

Provides access to the internal TList.Capacity property. The Capacity property specifies the allocated size of the array of pointers maintained by the TList object. This value is set to the number of pointers the list will need to contain.

Type:

int

Clear()

Clears all collection items

ClearAndResetID()

Embarcadero Technologies does not currently have any additional information.

Count

Returns the count of collection items

Delete(Index)

Deletes a single item from the collection.

EndUpdate()

Re-enables screen repainting.

FindItemID(ID: int) → CollectionItem

Returns the item with the specified ID. The FindItemID method returns the item in the collection whose ID property is passed to it as a parameter. If no item has the specified ID, FindItemID returns nil (Delphi) or NULL (C++).

GetEnumerator()

Returns a TCollection enumerator. GetEnumerator returns a TCollectionEnumerator reference, which enumerates all items in the collection. To do so, call the TCollectionEnumerator GetCurrent method within a While MoveNext do loop.

GetNamePath()

Returns a string used by the Object Inspector. If the collection has no owner, GetNamePath returns the name of the collection’s actual (runtime) type. If the collection is owned, GetNamePath returns the owner’s name followed, if applicable, by a dot and the name of the owner’s property that holds the collection. For example, GetNamePath might return “TreeView1.Items”.

Note: For a collection to have an owner, it must override the GetOwner method.

Insert(Index)

Inserts a new collection item to the collection at the Index position

IsEmpty

bool:

ItemClass

Indicates the class to which the collection’s items belong. ItemClass is the class (descended from TCollectionItem) to which the items in the collection belong. For example, in an instance of the TCollection descendant THeaderSections, the value of the ItemClass property is THeaderSection.

Type:

CollectionItemClass

Items

Returns an iterator over the collection items

Owner

Returns the Owner of the collection

Sort(AComparer: IComparer<System.Classes.CollectionItem>) → None

Embarcadero Technologies does not currently have any additional information.