WTL 自绘按钮为什么不显示图片。。。。。。

#pragma once

#include "stdafx.h"



class CODButtonImpl : public CWindowImpl<CODButtonImpl, CButton>,

					  public COwnerDraw<CODButtonImpl>

{

public:

	CODButtonImpl();



	BEGIN_MSG_MAP(CODButtonImpl)

		CHAIN_MSG_MAP_ALT(COwnerDraw<CODButtonImpl>, 1)

		DEFAULT_REFLECTION_HANDLER()

	END_MSG_MAP()



	void DrawItem ( LPDRAWITEMSTRUCT lpdis );



protected:

	CBitmap m_bmp;

};

#include "stdafx.h"

#include "CODButtonImpl.h"

#include "resource.h"





CODButtonImpl::CODButtonImpl()

{

	m_bmp.LoadBitmap ( IDB_ALYSON );

}



void CODButtonImpl::DrawItem ( LPDRAWITEMSTRUCT lpdis )

{

	CDCHandle dc = lpdis->hDC;

	CDC dcMem;



	dcMem.CreateCompatibleDC ( dc );

	dc.SaveDC();

	dcMem.SaveDC();



	// Draw the button's background, red if it has the focus, blue if not.

	if ( lpdis->itemState & ODS_FOCUS ) 

		dc.FillSolidRect ( &lpdis->rcItem, RGB(255,0,0) );

	else

		dc.FillSolidRect ( &lpdis->rcItem, RGB(0,0,255) );



	// Draw the bitmap in the top-left, or offset by 1 pixel if the button

	// is clicked.

	dcMem.SelectBitmap ( m_bmp );



	if ( lpdis->itemState & ODS_SELECTED ) 

		dc.BitBlt ( 1, 1, 80, 80, dcMem, 0, 0, SRCCOPY );

	else

		dc.BitBlt ( 0, 0, 80, 80, dcMem, 0, 0, SRCCOPY );



	dcMem.RestoreDC(-1);

	dc.RestoreDC(-1);

}

CODButtonImpl       m_wndODBtn;

	BEGIN_MSG_MAP(CMainDlg)

		MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)

		COMMAND_ID_HANDLER(ID_APP_ABOUT, OnAppAbout)

		COMMAND_ID_HANDLER(IDOK, OnOK)

		COMMAND_ID_HANDLER(IDCANCEL, OnCancel)

        COMMAND_ID_HANDLER_EX(IDC_ALYSON_BTN, OnAlysonODBtn)



	END_MSG_MAP()



	BEGIN_DDX_MAP(CMainDlg)

		DDX_CONTROL(IDC_ALYSON_BTN, m_wndODBtn)

	END_DDX_MAP()