Create without worrying of destroy a component

Problem/Question/Abstract:

How can I prevent resources leak.

Answer:

Make use of Interface characteristic where when the reference goes out of scope it will free itself.

type
  IAutoClean = interface
    ['{61D9CBA6-B1CE-4297-9319-66CC86CE6922}']
  end;

  TAutoClean = class(TInterfacedObject, IAutoClean)
  private
    FObj: TObject;
  public
    constructor Create(AObj: TObject);
    destructor Destroy; override;
  end;

implementation

constructor TAutoClean.Create(AObj: TObject);
begin
  FObj := AObj;
end;

destructor TAutoClean.Destroy;
begin
  FreeAndNil(FObj);
  inherited;
end;

Application....

procedure TForm1.Button1Click(Sender: TObject);
var
  a: IAutoClean;
    //must declare as local variable, so when this procedure finished, it's out of scope
  o: TOpenDialog; //any component
begin
  o := TOpenDialog.Create(self);
  a := TAutoClean.Create(o);
  if o.Execute then
    ShowMessage(o.FileName);
end;