求教关于DrawText的lprect参数问题

[sxj0384]

在mfc中查得该函数原型：
int DrawText( const CString& str, LPRECT lpRect, UINT nFormat );

其第二个参数是指向一个矩形的指针。使用时直接传入一个矩形怎么没报错？??
代码如下：

void CTextView::OnTimer(UINT nIDEvent) 
{
	// TODO: Add your message handler code here and/or call default
	m_nWidth += 5;
	
	CClientDC dc(this);
	TEXTMETRIC tm;
	dc.GetTextMetrics(&tm);

	CRect rect;
	rect.left = 0;
	rect.top = 200;
	rect.right = m_nWidth;
	rect.bottom = rect.top + tm.tmHeight;

	COLORREF clr = dc.SetTextColor(RGB(255,0,0));
	CString str;
	str.LoadString(IDS_STRINGVC);
	dc.DrawText(str,rect,DT_LEFT);
	
	rect.top = 150;
	//直接传入了rect矩形为何不报错？？？
         dc.DrawText(str,rect,DT_RIGHT);
	
	if(m_nWidth > dc.GetTextExtent(str).cx)
	{
		m_nWidth = 0;
		dc.SetTextColor(RGB(0,255,0));
		dc.TextOut(0,200,str);
	}

	CView::OnTimer(nIDEvent);
}

请大侠们指教谢谢了！！！

[renxu350]

重载，，，，，

[欣客]

virtual int DrawText(
LPCTSTR lpszString,
int nCount,
LPRECT lpRect,
UINT nFormat
);
int DrawText(
const CString& str,
LPRECT lpRect,
UINT nFormat
);



Parameters
lpszString
Points to the string to be drawn. If nCount is –1, the string must be null-terminated.

nCount
Specifies the number of chars in the string. If nCount is –1, then lpszString is assumed to be a long pointer to a null-terminated string and DrawText computes the character count automatically.

lpRect
Points to a RECT structure or CRect object that contains the rectangle (in logical coordinates) in which the text is to be formatted.(可以指向rect 结构指针或者CRect 对象。)

str
A CString object that contains the specified characters to be drawn.

nFormat
Specifies the method of formatting the text. It can be any combination of the values described for the uFormat parameter in DrawText in the Platform SDK. (combine using the bitwise OR operator):

[wltg2001]

已经重载了，所以不用指针是可以的

[zgl7903]

用的是 CRect 的 LPRECT 操作符
CRect::operator LPRECT

[sxj0384]

四楼正解 谢谢了！！