对于有背景图片的对话框上的按钮如何透明

这里是重载CButton类，类名为CMyButton

1.重载虚函数PreSubclassWindow()

void CMyButton::PreSubclassWindow() 
{
	// TODO: Add your specialized code here and/or call the base class
	ModifyStyle(0, BS_OWNERDRAW);//设置按钮类得自绘风格
	CButton::PreSubclassWindow();
}

2.重载DrawItem()

void CMyButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
	// TODO: Add your code to draw the specified item
	
	HDC hDestDC=lpDrawItemStruct->hDC;
  
	CRect rc;
    GetClientRect(rc);

    int nWindth=rc.Width();
    int nHeight=rc.Height();

	HDC hParentDC; 
	hParentDC=::GetDC(::GetParent(m_hWnd));  //获取父窗口dc

	HDC hDC=CreateCompatibleDC(lpDrawItemStruct->hDC);//创建兼容DC,   
    HBITMAP hBitmap=CreateCompatibleBitmap(lpDrawItemStruct->hDC,nWindth,nHeight); 
    HBITMAP hOldBitmap=(HBITMAP)SelectObject(hDC,hBitmap);


	SetBkMode(hDC,TRANSPARENT);

   //把父窗口的背景图复制到按钮的DC上,实现视觉透明----------------
    CAlarmClock2Dlg *pParent=(CAlarmClock2Dlg *)GetParent();
    
	CPoint pt(0,0);
    MapWindowPoints(pParent,&pt,1);
	::BitBlt(hDC,rc.left,rc.top,rc.Width(),rc.Height(),hParentDC,0,0,SRCCOPY);//不能少，不然按钮背景会为黑色

//====================================
	CString strText;
	GetWindowText(strText);

	HFONT hFont=(HFONT)SendMessage(WM_GETFONT);
	if(!hFont)
		hFont=(HFONT)GetStockObject(DEFAULT_GUI_FONT);

	HFONT hOldFont=(HFONT)SelectObject(hDC,hFont);

	::SetTextColor(hDC,RGB(255,0,0));
	::DrawText(hDC,strText,-1,&rc,DT_SINGLELINE|DT_CENTER|DT_VCENTER|DT_WORD_ELLIPSIS);
	::SelectObject(hDC,hOldFont);

	SelectClipRgn (hDC,NULL);
	//复制到控件的DC上------------------------
	BitBlt(hDestDC,0,0,nWindth,nHeight,hDC,0,0,SRCCOPY);

	//释放资源
	::SelectObject(hDC,hOldBitmap);
	::DeleteObject(hBitmap);
	::DeleteDC(hDC);
	::DeleteDC(hParentDC);

}

3.将按钮关联一个CMyButton类对象

运行效果如下：

参考：自绘实现半透明水晶按钮 -- 源码分享