在BeginThread方法中传递指向对象的指针

Type
Test = class

end;

TestIpl = class (Test)

end

然后我创建对象:

obj = TestIpl.Create();

BeginThread(nil, 0, @mtd, obj, 0, Threadinfo.ThreadId);

在method:mtd中,我想使用created object,所以我将其转换为:

var 
  obj: Test;
begin
obj :=  Test(DataParameter);

我做得对吗,但更重要的是。能这样做吗? 我很担心将指针投射到其原始对象的行。这样行吗?

目前,当我想在testIpl中使用重载方法时,我得到AV。

编辑

function mtd(DataParameter: Pointer): DWORD; stdcall;

测试用例

unit Unit2;

interface

Type
  Test = class
  protected
    function Test(): Integer; virtual;
  end;

  TestIpl = class (Test)
  protected
    function Test(): Integer; override;
  end;

procedure TestCase;

implementation

function RunThread(Parameter: Pointer): Integer;
var
  x: Test;
  Rslt: Integer;
begin
  x := Test(Parameter);

  Rslt := x.Test();
end;


procedure TestCase;
var
  test: TestIpl;
  ThreadId: Cardinal;
begin
  test := TestIpl.Create;

  BeginThread(nil, 0, Addr(RunThread), Addr(test), 0, ThreadId);
end;

{ Test }

function Test.Test: Integer;
begin
  Result := 1;
end;

{ TestIpl }

function TestIpl.Test: Integer;
begin
  Result := 2;
end;

end.