windows – PrintWindow位图与PrintScreen Key位图不同

但如果我尝试使用Windows API以编程方式进行,我会得到：

为什么会出现差异？我如何以编程方式获得第一个？

这是我的代码：

[DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool PrintWindow(IntPtr hWnd,IntPtr hdcBlt,int nFlags);

    public Bitmap PrintWindow()
    {
        Bitmap bmp = new Bitmap(windowRect.Width,windowRect.Height,PixelFormat.Format32bppArgb);
        Graphics gfxBmp = Graphics.FromImage(bmp);
        IntPtr hdcBitmap = gfxBmp.GetHdc();

        bool success = PrintWindow(windowHandle,hdcBitmap,0);
        gfxBmp.ReleaseHdc(hdcBitmap);

        if (!success)
        {
            Console.WriteLine("Error copying image");
            Console.WriteLine(getLastError());
        }

        gfxBmp.Dispose();

        return bmp;
    }

更新：
使用BitBlt做同样的事情.

这是code from CodeProject仍然返回黑色蒙版图像：

public Image CaptureWindow(IntPtr handle)
{
    // get te hDC of the target window
    IntPtr hdcSrc = User32.GetWindowDC(handle);
    // get the size
    User32.RECT windowRect = new User32.RECT();
    User32.GetWindowRect(handle,ref windowRect);
    int width = windowRect.right - windowRect.left;
    int height = windowRect.bottom - windowRect.top;
    // create a device context we can copy to
    IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
    // create a bitmap we can copy it to,// using GetDeviceCaps to get the width/height
    IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc,width,height);
    // select the bitmap object
    IntPtr hOld = GDI32.SelectObject(hdcDest,hBitmap);
    // bitblt over
    GDI32.BitBlt(hdcDest,height,hdcSrc,CopyPixelOperation.SourceCopy | CopyPixelOperation.CaptureBlt);
    // restore selection
    GDI32.SelectObject(hdcDest,hOld);
    // clean up
    GDI32.DeleteDC(hdcDest);
    User32.ReleaseDC(handle,hdcSrc);
    // get a .NET image object for it
    Image img = Image.FromHbitmap(hBitmap);
    // free up the Bitmap object
    GDI32.DeleteObject(hBitmap);

    img.Save("SampleImage.png");
    return img;
}

我尝试了很多CopyPixelOperation的组合(大约有131,000个中的15,000个),但它仍然不起作用.

使用Windows 8,AMD Radeon HD 6870.

更新2

看起来窗户是透明的,允许窗户的蓝色渗透.当我将窗口颜色更改为黑色时(使用Windows个性化对话框),我得到的内容大致类似于第二个窗口.但边界仍然缺失.

我还没有找到解决方案,但它能够深入了解问题.