动态创办的ComboBox控件，添加OnDrawItem事件是报错

动态创建的ComboBox控件，添加OnDrawItem事件是报错
[BCC32 Error] test.cpp(43): E2034 Cannot convert 'void (_fastcall * (_closure )(TWinControl *,int,TRect &,TOwnerDrawState))(TWinControl *,int,TRect &,TOwnerDrawState)' to 'TDrawItemEvent'
  Full parser context
  test.cpp(32): parsing: void _fastcall TForm1::Button1Click(TObject *)

请教一下，我动态的创建了一个ComboBox控件，添加了OnDrawItem事件，结果报错，找不到原因，Help

[解决办法]
TRect 加一个const 就好了

C/C++ code

class TForm1 : public TForm{__published:    // IDE-managed Components    TComboBox *ComboBox1;    void __fastcall ComboBox1DrawItem(TWinControl *Control, int Index,          TRect &Rect, TOwnerDrawState State);    void __fastcall myComboBox1DrawItem(TWinControl *Control, int Index,          const TRect &Rect, TOwnerDrawState State);    void __fastcall FormCreate(TObject *Sender);private:    // User declarationsTComboBox *ComboBox2;public:        // User declarations    __fastcall TForm1(TComponent* Owner);};
[解决办法]
VCL组件的事件处理函数，声明定义最好与事件的处理函数原型保持一致。