Delphi - 将变量指针作为字符串传递给另一个函数

Question

我不知道这是否可能，但我需要的是通过它的指针访问(使用和释放)TStream 变量，将字符串参数传递给另一个函数。

这是我尝试做的“不工作”的例子:

procedure TForm1.Button1Click(Sender: TObject);
var
  Stm: TMemoryStream;
begin
  Stm := TMemoryStream.Create;
  try
    Memo.Lines.SaveToStream(Stm);
    Stm.Position := 0;
    Memo.Clear;
    Edit.Text := IntToStr(Integer(@Stm));
  except
    Stm.Free;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  PStm: ^TMemoryStream;
begin
  PStm := Pointer(StrToInt(Edit.Text));
  try
    Memo.Lines.LoadFromStream(PStm^);  // <--- Access Violation
  finally
    PStm^.Free;
  end;
end;

感谢您帮助解决这个问题!

Answer 1

TStream 是一个引用类型。您的 Stm 变量包含指向流对象实例的指针。你想传递这个指针值，而不是局部变量的地址。这是固定代码:

procedure TForm1.Button1Click(Sender: TObject);
var
  Stm: TMemoryStream;
begin
  Stm := TMemoryStream.Create;
  try
    Memo.Lines.SaveToStream(Stm);
    Stm.Position := 0;
    Memo.Clear;
    Edit.Text := IntToStr(Integer(Stm));
  except
    Stm.Free;
    raise;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  Stm: TMemoryStream;
begin
  Stm := Pointer(StrToInt(Edit.Text));
  try
    Memo.Lines.LoadFromStream(Stm);
  finally
    Stm.Free;
  end;
end;