'System.Runtime.InteropServices.ExternalException‘

Question

我在第70行"img3.Save(finalImage，System.Drawing.Imaging.ImageFormat.Jpeg);“上不断收到'System.Runtime.InteropServices.ExternalException‘的错误。最初我有一个程序，可以将两张照片拼接在一起，但我希望两张照片的大小相同(300Pixles X 300Pixles)，所以我插入了一个方法：

public static Image resizeImage(Image imgToResize, Size size)
{
    return (Image)(new Bitmap(imgToResize, size));
}

在我的CombineImages方法中put：

img = resizeImage(img, new Size(300, 300));

但是现在我得到了一个错误。下面是我的代码：

    private void cmdCombine_Click(object sender, EventArgs e)
    {
        //Change the path to location where your images are stored.
        DirectoryInfo directory = new DirectoryInfo(@"C:\Users\Elder Zollinger\Desktop\Images");
        if (directory != null)
        {
            FileInfo[] files = directory.GetFiles();
            CombineImages(files);
        }

    }
    private void CombineImages(FileInfo[] files)
    {
        //change the location to store the final image.
        string finalImage = @"C:\Users\Elder Zollinger\Desktop\Images\Final.jpg";
        List<int> imageHeights = new List<int>();
        int nIndex = 0;
        int width = 0;
        foreach (FileInfo file in files)
        {
            Image img = Image.FromFile(file.FullName);
            img = resizeImage(img, new Size(300, 300));
            imageHeights.Add(img.Height);
            width += img.Width;
            img.Dispose();
        }
        imageHeights.Sort();
        int height = imageHeights[imageHeights.Count - 1];
        Bitmap img3 = new Bitmap(width, height);
        Graphics g = Graphics.FromImage(img3);
        g.Clear(SystemColors.AppWorkspace);
        foreach (FileInfo file in files)
        {
            Image img = Image.FromFile(file.FullName);
            if (nIndex == 0)
            {
                g.DrawImage(img, new Point(0, 0));
                nIndex++;
                width = img.Width;
            }
            else
            {
                g.DrawImage(img, new Point(width, 0));
                width += img.Width;
            }
            img.Dispose();
        }
        g.Dispose();
        img3.Save(finalImage, System.Drawing.Imaging.ImageFormat.Jpeg);
        img3.Dispose();
        imageLocation.Image = Image.FromFile(finalImage);
    }
    public static Image resizeImage(Image imgToResize, Size size)
    {
        return (Image)(new Bitmap(imgToResize, size));
    }
}

}

Answer 1

上传图片的图片格式可能无法直接转换为Jpeg格式。调整大小时，我们要做的一件事就是将图像绘制到一个新的Graphics实例中，如下所示。请注意，前两行试图直接从原始图像实例中获取像素和图像格式-您可能会在使用CMYK和带有透明层(GIF/PNG)的图像时遇到问题。

            var pixelFormat = imgToResize.PixelFormat;
            var imageFormat = imgToResize.RawFormat;

            Bitmap b = new Bitmap(newWidth.Value, newHeight.Value, pixelFormat);
            Graphics g = Graphics.FromImage(b);

            g.SmoothingMode = SmoothingMode.AntiAlias;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.PixelOffsetMode = PixelOffsetMode.HighQuality;

            g.DrawImage(imgToResize, (float)-0.5, (float)-0.5, newWidth.Value + 1, newHeight.Value + 1);
            g.Dispose();

            b.Save(stream, imageFormat);