[Overview][Constants][Types][Classes][Procedures and functions][Variables][Index] | Reference for unit 'Classes' (#rtl)

# TList

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

Class to manage collections of pointers.

## Declaration

Source position: classesh.inc line 298

`type TList = class(TObject, IFPObserved)`
`public`
`constructor Create;` |  | Class to manage collections of pointers.
`destructor Destroy; override;` |  | Destroys the list and releases the memory used to store the list elements.
`procedure FPOAttachObserver();` |  | Add an observer to the list of observers
`procedure FPODetachObserver();` |  | Remove an observer from the list of observers
`procedure FPONotifyObservers();` |  | Notify observers of changes in the list
`procedure AddList();` |  | Add all pointers from another list
`function Add();` |  | Adds a new pointer to the list.
`procedure Clear; virtual;` |  | Clears the pointer list.
`procedure Delete();` |  | Removes a pointer from the list.
`class procedure Error(); virtual;` |  | Raises an EListError exception.
`procedure Exchange();` |  | Exchanges two pointers in the list.
`function Expand;` |  | Increases the capacity of the list if needed.
`function Extract();` |  | Remove the first occurrence of a pointer from the list.
`function First;` |  | Returns the first non-nil pointer in the list.
`function GetEnumerator;` |  | Create an IEnumerator instance
`function IndexOf();` |  | Returns the index of a given pointer.
`procedure Insert();` |  | Inserts a new pointer in the list at a given position.
`function Last;` |  | Returns the last non-nil pointer in the list.
`procedure Move();` |  | Moves a pointer from one position in the list to another.
`procedure Assign();` |  | Copy the contents of other lists.
`function Remove();` |  | Removes a value from the list.
`procedure Pack;` |  | Removes Nil pointers from the list and frees unused memory.
`procedure Sort();` |  | Sorts the pointers in the list.
`property Capacity: Integer; [rw]` |  | Current capacity (i.e. number of pointers that can be stored) of the list.
`property Count: Integer; [rw]` |  | Current number of pointers in the list.
`property Items []: Pointer; default; [rw]` |  | Provides access to the pointers in the list.
`property List: PPointerList; [r]` |  | Memory array where pointers are stored.
`end;`

## Inheritance

`TList,IFPObserved` |  | Class to manage collections of pointers.
`TObject` |  | Base class of all classes.

## Description

TList is a class that can be used to manage collections of pointers. It introduces methods and properties to store the pointers, search in the list of pointers, sort them. It manages its memory by itself, no intervention for that is needed. It has an event notification mechanism which allows to notify of list changes. This slows down some of TList mechanisms, and if no notification is used, TFPList may be used instead.

To manage collections of strings, it is better to use a TStrings descendant such as TStringList. To manage general objects, a TCollection class exists, from which a descendant can be made to manage collections of various kinds.

## See also

TStrings |  | Class to manage arrays or collections of strings
TCollection |  | Base class to manage collections of named objects.