Vector i delphi?

Jeg tror altså at du bliver nødt til at gemme pointere

Det gør Java Vector jo også.

(alle objekter i java er reelt en pointer !)

Delphi's TList

function Add(Item: Pointer): Integer Adds Item to the end of the list.
procedure Clear Deletes all items from the list.
procedure Delete(Index: Integer) Deletes the item at the given Index.
procedure Exchange(Index1, Index2) Swaps the items at Index1 and Index2.
function Expand: TList Increases the size of the list.
function First: Pointer Returns Items[0].
function IndexOf(Item: Pointer): Integer Returns the index of the first item to match Item.
procedure Insert(Index: Integer; Item: Pointer) Inserts the item at position Index.
function Last: Pointer Returns Items[Count-1].
procedure Move(CurIndex, NewIndex: Integer) Moves the item at CurIndex to NewIndex.
procedure Pack Deletes all nil items.
function Remove(Item: Pointer): Integer Deletes the first item that matches Item.
property Capacity: Integer Sets or gets the number of available slots where list items can be stored.
property Count: Integer Sets or gets the number of items in the list.
property Items[Index: Integer]: Pointer; default Sets or gets the item at position Index.
property List: PPointerList Returns a pointer to the array where TList stores its items.



Java's Vector:

add(int index, Object element)
add(Object o)
addAll(Collection c)
addAll(int index, Collection c)
addElement(Object obj)
capacity()
clear()
clone()
contains(Object elem)
containsAll(Collection c)
copyInto(Object[] anArray)
elementAt(int index)
elements()
ensureCapacity(int minCapacity)
size()
removeElement(Object obj)
.......




Forskellen er vel at man med Vectoren kan gemme object ref, og så klarer java resten, hvor man i Delphi selv skal håndterer "det hele".



MEN Delphi har faktisk en TStringList, som minder rigtig meget om Java's Vector:

var
  sl : TStringList;
  i      : Integer;
begin

  sl := TStringList.Create;


  sl.Add('string1');
  sl.Add('string2');
  sl.Add('string3');


  for i := 0 to sl.Count-1 do
    ShowMessage(sl[i]);
end;




Men problemmet er bare at man kun kan gemme String's i en StringList, og en string i delphi er jo ikke et object.

Men mon ikke der findes den "Vector" type i Delphi.
Nogen må vide det....

Prøv at kigge på følgende, ved ikke om det kan bruges:

StringList.Objects : property Objects[Index: Integer]: TObject;

StringList.AddObject : function AddObject(const S: string; AObject: TObject): Integer; override;

StringList.InsertObject : procedure InsertObject(Index: Integer; const S: string; AObject: TObject); override;

StringList.IndexOfName : function IndexOfName(const Name: string): Integer; virtual;

StringList.IndexOfObject : function IndexOfObject(AObject: TObject): Integer;virtual;

Kig i hjælpen for mere info.

TObjectList var løsningen


The first is the TListDataSet component, a dataset supporting navigation among the data of a TObjectList. This is one of the new Delphi 5 container classes, which only slightly differs from TList. It uses objects instead of pointers (nothing really different, from a technical point of view) and has the ability to destroy the objects in the list when the list is destroyed or cleared.