mfc 按钮从绘贴图

#pragma once
#include "afxwin.h"

#define BTN_WIDTH 36
#define BTN_HIGHT 36

class CSplitButton :public CButton
{
public:
	CSplitButton(void);
	~CSplitButton(void);

	void LoadImg(const char* strPath);
	void selectBtn(bool bselect);
	virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);

private:
	CBitmap m_bmpImg;
	bool m_bselect;
};

#include "StdAfx.h"
#include "SplitButton.h"


CSplitButton::CSplitButton(void):m_bselect(false)
{
}


CSplitButton::~CSplitButton(void)
{
	m_bmpImg.DeleteObject();
}

void CSplitButton::LoadImg(const char* strPath)
{

	HBITMAP hBitmap =(HBITMAP)::LoadImage(   
		NULL,   
		strPath,							// 图片全路径  
		IMAGE_BITMAP,						// 图片格式  
		0,0,   
		LR_LOADFROMFILE|LR_CREATEDIBSECTION);
	
	m_bmpImg.Attach(hBitmap);
}

void CSplitButton::selectBtn(bool bselect)
{
	m_bselect = bselect;
	Invalidate();
}

void CSplitButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{

	// TODO:  添加您的代码以绘制指定项
	CRect lRect;  
	GetClientRect(&lRect);
	CDC dc;
	dc.Attach(lpDrawItemStruct->hDC); //得到设备环境类CDC

	if (m_bselect/*lpDrawItemStruct->itemState & ODS_SELECTED*/)
	{
		COLORREF DownColor = RGB(209,208,208);
		CBrush brush(DownColor);
		dc.FillRect(&(lpDrawItemStruct->rcItem),  &brush);
	}
	else
	{
		COLORREF DownColor = RGB(239,239,239);
		CBrush brush(DownColor);
		dc.FillRect(&(lpDrawItemStruct->rcItem),  &brush);
	}
	
	CDC dcMem;
	dcMem.CreateCompatibleDC(&dc);  //内存
	//位图加载到内存dc中  
	CBitmap *pOldBitmap=dcMem.SelectObject(&m_bmpImg);  

	BITMAP bmp;
	m_bmpImg.GetBitmap(&bmp); //获取位图信息

	int x = (lRect.Width() - bmp.bmWidth)/2;
	int y = (lRect.Height() - bmp.bmHeight)/2;
	dc.StretchBlt(x,y,bmp.bmWidth,bmp.bmHeight,&dcMem,0,0,bmp.bmWidth,bmp.bmHeight,SRCCOPY);  
	//清理  
	dcMem.SelectObject(&pOldBitmap);
}

效果：