MFC修改编辑框光标显示位置方法详解

void MyComboBox::PreSubclassWindow()
{
	CComboBox::PreSubclassWindow();
	
 	COMBOBOXINFO   comboInfo;
 
 	//获取控件信息
 	comboInfo.cbSize = sizeof(COMBOBOXINFO);
 	GetComboBoxInfo(&comboInfo);
 	//子类化编辑框
 	if (comboInfo.hwndItem != nullptr )
 	{
		if ( !((GetStyle() & CBS_DROPDOWNLIST) == CBS_DROPDOWNLIST))
 			m_editCtrl.SubclassWindow(comboInfo.hwndItem);
		
 	}
}

afx_msg  void OnNcCalcSize(BOOL bCalcValidRects, NCCALCSIZE_PARAMS* lpncsp);

BEGIN_MESSAGE_MAP(MyComboBox, CComboBox)
	ON_WM_NCCALCSIZE()
END_MESSAGE_MAP()

void MyComboBox::OnNcCalcSize(BOOL bCalcValidRects, NCCALCSIZE_PARAMS* lpncsp)
{
	//获取字体的属性
	CFont		*font	= GetFont();
	LOGFONT  lf;
	font->GetLogFont(&lf);

	LONG nFontHeight = 0;
	nFontHeight = lf.lfHeight < 0 ? -lf.lfHeight :  lf.lfHeight;
	
	COMBOBOXINFO   comboInfo;
	//获取控件信息 
	comboInfo.cbSize = sizeof(COMBOBOXINFO);
	GetComboBoxInfo(&comboInfo);
	CRect   rectEdit = comboInfo.rcItem;
	rectEdit.top += (rectEdit.Height()-nFontHeight)/2 -3;
	m_editCtrl.MoveWindow(rectEdit);

	CComboBox::OnNcCalcSize(bCalcValidRects , lpncsp);
}

afx_msg BOOL OnEraseBkgnd(CDC *pDC);

BEGIN_MESSAGE_MAP(MyComboBox, CComboBox)
	ON_WM_ERASEBKGND()
END_MESSAGE_MAP()

BOOL MyComboBox::OnEraseBkgnd(CDC *pDC)
{
	CRect  rect;
	GetClientRect(rect);
	pDC->FillSolidRect(&rect , RGB(255 , 255 , 255));
	return FALSE;
	//return CComboBox::OnEraseBkgnd(pDC);
}