MFC C++ Screenshot - c++

Question

I have an application that has drawn a grid using CDC (it has text, rectangle, and bitmaps). I want to take a screenshot of that finished grid when it is saved and use that screenshot as a "preview" for the file.
How can I take a screenshot of my application and save it?
Thank you,

Answer 1

Answer is here
void CScreenShotDlg::OnPaint()
{
// device context for painting
CPaintDC dc(this);
// Get the window handle of calculator application.
HWND hWnd = ::FindWindow( 0, _T( "Calculator" ));
// Take screenshot.
PrintWindow( hWnd,
dc.GetSafeHdc(),
0 );
}

Answer 2

Ultimately I ended up doing it this way because I wanted to capture even the hidden parts of the window (since the content extends beyond the screen and requires scrolling):
CDC* WindowToCaptureDC = AfxGetMainWnd()->GetWindowDC();
CDC CaptureDC;
CDC MemDC;
MemDC.CreateCompatibleDC(WindowToCaptureDC);
CaptureDC.CreateCompatibleDC(WindowToCaptureDC);
CBitmap CaptureBmp;
CBitmap ResizeBmp;
int pWidth = grid.tableWidth + grid.marginLeft*2;
int pHeight = grid.tableHeight + grid.marginBottom;
CaptureBmp.CreateCompatibleBitmap( WindowToCaptureDC, pWidth, pHeight);
CaptureDC.SelectObject(&CaptureBmp);
CBrush brush(RGB(255, 255, 255));
CaptureDC.SelectObject(&brush);
CaptureDC.Rectangle(0, 0, pWidth, pHeight);
///Drew items into CaptureDC like I did for OnDraw HERE///
double width = //desired width;
double height = //desired width;
//maintain aspect ratio
if(pWidth!=width || pHeight!=height)
{
double w = width/pWidth;
double h = height/pHeight;
if(w < h)
height = height*w;
else
width = width*h;
}
ResizeBmp.CreateCompatibleBitmap(WindowToCaptureDC, width, height);
MemDC.SelectObject(&ResizeBmp);
MemDC.StretchBlt(0, 0, width, height, &CaptureDC, 0, 0, pWidth, pHeight, SRCCOPY);
CImage TempImageObj;
TempImageObj.Attach((HBITMAP)ResizeBmp.Detach());
CString filePath = _T("LOCATION\\image.bmp");
TempImageObj.Save(filePath);