今天写了一个函数为把两图片合并，并且可以循环添加图片，但是出现错误，看了半天还是找不出来，大虾们帮忙看看

HBITMAP CMainFrame::AddCopyScreenToBitmap(LPRECT lpRect) 
{
ShowWindow(SW_SHOW);
HDC hScrDC, hMemDC; 
HBITMAP hOldBitmap;
int nX, nY, nX2, nY2; 
int nWidth, nHeight; 
int xScrn, yScrn; 
if (IsRectEmpty(lpRect)) 
return NULL; 
hScrDC = CreateDC(_T("DISPLAY"), NULL, NULL, NULL); 
hMemDC = CreateCompatibleDC(hScrDC); 
nX = lpRect->left; 
nY = lpRect->top; 
nX2 = lpRect->right; 
nY2 = lpRect->bottom; 
xScrn = GetDeviceCaps(hScrDC, HORZRES); 
yScrn = GetDeviceCaps(hScrDC, VERTRES); 
if (nX < 0) nX = 0; 
if (nY < 0) nY = 0; 
if (nX2 > xScrn) nX2 = xScrn; 
if (nY2 > yScrn) nY2 = yScrn; 
nWidth = nX2 - nX; 
nHeight = nY2 - nY; 
HBITMAP hBitmap1 = CreateCompatibleBitmap(hScrDC, nWidth, nHeight); 
hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap); 
//ShowWindow(SW_HIDE); 
BitBlt(hMemDC, 0, 0, nWidth, nHeight,hScrDC, nX, nY, SRCCOPY); 
hBitmap1 =(HBITMAP)SelectObject(hMemDC, hOldBitmap); 

BITMAP bm;
GetObject( hBitmap, sizeof(BITMAP), &bm); HDC hdc = CreateDC(_T("DISPLAY1"), NULL, NULL, NULL);  HDC hSrcDC1 = CreateCompatibleDC(hdc);
HDC hSrcDC2 = CreateCompatibleDC(hdc);
HBITMAP hbm = CreateCompatibleBitmap(hdc,nWidth,bm.bmHeight + nHeight); hOldBitmap = (HBITMAP)SelectObject(hdc,hbm);
SelectObject(hSrcDC1,hBitmap);
SelectObject(hSrcDC2,hBitmap1); BitBlt(hdc,0,0,bm.bmWidth,bm.bmHeight,hSrcDC1,0,0,SRCCOPY);
BitBlt(hdc,0,0,nWidth,nHeight,hSrcDC2,0,0,SRCCOPY); hBitmap =(HBITMAP)SelectObject(hdc,hOldBitmap); 
DeleteDC(hSrcDC1); 
DeleteDC(hSrcDC2); 
DeleteDC(hdc); 
DeleteObject(hbm);
DeleteDC(hScrDC); 
DeleteDC(hMemDC); 

ShowWindow(SW_SHOW); 
return hBitmap; 
}