Как автоматически расширить TEdit

unit ExpandingEdit;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TExpandingEdit = class(TEdit)
  private
    FCanvas: TControlCanvas;
  protected
    procedure Change; override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
end;

procedure register;

implementation

constructor TExpandingEdit.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FCanvas := TControlCanvas.Create;
  FCanvas.Control := Self;
end;

destructor TExpandingEdit.Destroy;
begin
  FCanvas.Free;
  inherited Destroy;
end;

procedure TExpandingEdit.Change;
const
  EditMargin = 8;
var
  W: Integer;
begin
  inherited Change;
  if not HandleAllocated then
    Exit;
  FCanvas.Font := Font;
  W := FCanvas.TextWidth(Text) + (2 * EditMargin);
  if (Width < W) then
    Width := W;
end;

procedure register;
begin
  RegisterComponents('Samples', [TExpandingEdit]);
end;

end.