如何创建自定义组件?访问专用字段时出错

标题:

class PACKAGE TMyClass : public TPanel
{
private:
    TObject *obj;
protected:
public:
   __fastcall TMyClass(TComponent* Owner);
   void Stuff();
};

CPP文件:

__fastcall TMyClass::TMyClass(TComponent* Owner)
   : TPanel(Owner)
{
    Caption        = "";
    DoubleBuffered = True;
    Width          = 385;
    Height         = 65;

    TObject *obj= new TObject;     //obj gets an address here
}



void TMyClass::Stuff()      // <---- I call this method in the OnClick event of a button.
{
   Caption = obj->ClassName();    //obj is NULL here
}
//---------------------------------------------------------------------------








namespace Uvolctrl
{ void __fastcall PACKAGE Register()
   {  TComponentClass classes[1] = {__classid(TMyClass)};
       RegisterComponents(L"Samples", classes, 0); } }



static inline void ValidCtrCheck(TMyClass *)   // assure that the components do not have any pure virtual functions.
{ new TMyClass(NULL);    }