Hi Folks,

I'm not sure where this post belongs since I'm using managed vc.net, but the
issue is around GDI BitBlt.

Here is a summary of the problem:
- I am trying to copy a bitmap of my main form into a picture box.
- To do this, I bitblt using the device contexts of the form and a bitmap
object.
- After blitting, the bitmap image is always blank.  I don't understand what
I'm doing wrong here.

Here is my relevant code:

MainMenuForm_Shown(...)
{
   Graphics ^formGraphics = this->CreateGraphics();
   Bitmap    ^bitmap = gcnew Bitmap(this->Width, this->Height, formGraphics);
   Graphics ^bitmapGraphics = Graphics::FromImage(bitmap);
   IntPtr formDC = formGraphics->GetHdc();
   IntPtr bitmapDC = bitmapGraphics->GetHdc();

   BitBlt(bitmapDC, 0, 0, this->Width, this->Height, formDC, 0, 0, 0xCC0020);

   formGraphics->ReleaseHdc(formDC);
   bitmapGraphics->ReleaseHdc(bitmapDC);

   bitmap->Save(CCarthageDefs::DIR_IMAGES + "test.jpg");
}

After running the above code, the file test.jpg is tiny and basically blank
(maybe all solid grayish white).  I expected it to be a copy of the form.  
Any comments on why this is happening would be most appreciated.

I thought maybe the problem was with the form, so I tried an even simpler
test: copying one image to another.  Here is the code:
     Bitmap    ^srcImage = gcnew Bitmap("input.jpg");
     Graphics ^srcG = Graphics::FromImage(srcImage);
     Bitmap ^toImage  = gcnew Bitmap(srcImage->Width, srcImage->Height,
                                                               srcG);
     Graphics ^toG  = Graphics::FromImage(toImage);

     IntPtr srcDc = srcG->GetHdc();
     IntPtr toDc  = toG->GetHdc();

     BitBlt(toDc, 0, 0, srcImage->Width, srcImage->Height, srcDc, 0, 0,
                0xCC0020);

     srcG->ReleaseHdc(srcDc);
     toG->ReleaseHdc(toDc);
     
     srcImage->Save(CCarthageDefs::DIR_IMAGES + "test1.jpg");
     toImage->Save(CCarthageDefs::DIR_IMAGES + "test2.jpg");
---
After running the above code, test1.jpg (an output of the source image) is a
correct copy of the source image.  test2.jpg is *blank*??  Again, something
with the BitBlt seems to have failed ...

Also, to make sure I was actually hitting the genuine BitBlt code, I tried
using the options BLACKNESS and WHITENESS.  Both worked ... the destination
turned the appropriate color.

Finally, in case anyone is interested in why I'm doing this ... I am having
some ugly flicker at the load-up of my form.  I'm trying to take a copy of
the form's look, put it in a screen-sized picture box, and display that to
the user before they see the real form.

Thanks