请高手执教

[linyang0106linyang]

同样的一段代码在主的对话框中好用
在其他对话框中为什么不好用啊

CPaintDC dc(this);
CDC mDC;
mDC.CreateCompatibleDC(&dc);
CBitmap bitmap;
CRect r(CPoint(0,0),CSize(50,50));
bitmap.CreateCompatibleBitmap(&dc,r.Size().cx,r.Size().cy);
CBitmap* pOldBitmap=mDC.SelectObject(&bitmap);
CBrush brush;
brush.CreateSolidBrush(0);
mDC.FillRect(&r,&brush);
mDC.SetTextColor(255);
mDC.SetBkColor(0);
mDC.TextOut(10,10,"好了");
dc.BitBlt(0,0,r.Size().cx,r.Size().cy,&mDC,0,0,SRCCOPY);
CImage img;
img.Attach(bitmap);
img.Save("out.jpeg");