请问我下边这段代码怎么总是出错呢？总是出现这样的错误：MIplImage img =(MIplImage)Marshal.PtrToStructure(src, typeof(MIplImage));-----未将对象引用设置到对象实例？

这段代码是实现IntPtr向Image<>类型的转化。
public Image ShowIplImageInWindow(IntPtr src)
        {
            MIplImage img =(MIplImage)Marshal.PtrToStructure(src, typeof(MIplImage));

            Bitmap disp = new Bitmap(img.width, img.height, PixelFormat.Format24bppRgb);
            BitmapData bmp = disp.LockBits(new Rectangle(0, 0, img.width, img.height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);

            long linebytes = (img.width * 24 + 31) / 32 * 4;

            unsafe
            {
                byte* pixel = (byte*)bmp.Scan0.ToPointer();
                if (img.nChannels == 3)
                {
                    for (int i = 0; i < img.height; i++)
                    {
                        for (int j = 0, n = 0; j < img.width; j++, n++)
                        {
                            byte b = ((byte*)img.imageData + img.widthStep * i)[3 * j];
                            byte g = ((byte*)img.imageData + img.widthStep * i)[3 * j + 1];
                            byte r = ((byte*)img.imageData + img.widthStep * i)[3 * j + 2];

                            *(pixel + linebytes * (i) + n) = b;
                            n++;
                            *(pixel + linebytes * (i) + n) = g;
                            n++;
                            *(pixel + linebytes * (i) + n) = r;
                        }
                    }
                }
                else if (img.nChannels == 1)
                {
                    for (int i = 0; i < img.height; i++)
                    {
                        for (int j = 0, n = 0; j < img.width; j++, n++)
                        {
                            byte g = ((byte*)img.imageData + img.widthStep * i)[j];

                            *(pixel + linebytes * (i) + n) = g;
                            n++;
                            *(pixel + linebytes * (i) + n) = g;
                            n++;
                            *(pixel + linebytes * (i) + n) = g;
                        }
                    }
                }
                else
                {
                    return null;
                }
            }

            disp.UnlockBits(bmp);

            return (Image)disp;
        }

我已经解决了 \(^o^)/~