delphi – 没有引用计数的接口

在尝试了整整一个下午后,我放弃了！

当我调用FreeAndNil(p)时,为什么会出现访问冲突？

以下是我的简单单元的完整列表.

unit fMainForm;

interface

uses
  Windows,messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,StdCtrls;

type
  TForm4 = class(TForm)
    btn1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure btn1Click(Sender: TObject);
  end;

type
  IPersona = interface(IInterfacE)
  ['{44483AA7-2A22-41E6-BA98-F3380184ACD7}']
    function GetNome: String;
    procedure SetNome(const Value: String);
    property Nome: String read GetNome write SetNome;
  end;

type
  TPersona = class(TObject,IPersona)
  Strict private
    FNome: String;
    function GetNome: String;
    procedure SetNome(const Value: String);
  protected
    function _AddRef: Integer; stdcall;
    function _Release: Integer; stdcall;
    function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
  public
    constructor Create(const ANome: String);
    destructor Destroy; override;
  end;

var
  Form4: TForm4;

implementation

{$R *.dfm}

procedure TForm4.FormCreate(Sender: TObject);
begin
  ReportMemoryLeaksOnShutdown := True;
end;

procedure TForm4.btn1Click(Sender: TObject);
var
  p: IPersona;
begin
  p := TPersona.Create('Fabio');
  try
    Showmessage(p.NomE);
  finally
    FreeAndNil(p);
  end;
end;

constructor TPersona.Create(const ANome: String);
begin
  inherited Create;
  FNome := ANome;
end;

destructor TPersona.Destroy;
begin
  inherited Destroy;
end;

function TPersona._AddRef: Integer;
begin
  Result := -1
end;

function TPersona._Release: Integer;
begin
  Result := -1
end;

function TPersona.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
  if GeTinterface(IID,Obj) then
    Result := S_OK
  else
    Result := E_NOINTERFACE;
end;

function TPersona.GetNome: String;
begin
  Result := FNome;
end;

procedure TPersona.SetNome(const Value: String);
begin
  FNome := Value;
end;

end.