[Lazarus] Example of TObjectList sorting

[Denis Kozlov]

On 9 May 2016 at 12:48, Richard Mace <richard.mace at gmail.com> wrote:

> I have a TObjectList that contains many objects that have a property
> called "Position" which is an integer.
>
> Could somebody show me an example of the code that I will need to create
> that will sort all of my Objects within the TObjectList so that they are in
> position order e.g. 1,2,3,4,5 and so on?
>

Call TList.Sort method and supply a comparison function.


For example:

List.Sort(@CompareByPositionPtr);

function CompareByPosition(A, B: TMyObject): Integer; inline;
begin
  if A.Position < B.Position then
    Result := -1
  else if A.Position > B.Position then
    Result := 1
  else
    Result := 0;
end;

function CompareByPositionPtr(A, B: Pointer): Integer;
begin
  Result := CompareByPosition(TMyObject(A), TMyObject(B));
end;


This kind of question is better suited on the forum I think

Denis
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