GDI+ System.Runtime.InteropServices.ExternalException 图像调整大小和转换

Question

ImageHandler class负责将图片转为jpg和60x60大小，然后转为Base64。第一张图片很好，但是当我尝试在同一运行中处理另一张图片时，它崩溃了。

class ImageHandler
    {
        public static void convertToFormat(string filename)
        {
            var image = Image.FromFile(@filename);
            var bitmap = ResizeImage(image, Globals.ImageSize, Globals.ImageSize);
            bitmap.Save(Globals.PRED_PATH, ImageFormat.Jpeg);
        }

        public static Bitmap ResizeImage(Image image, int width, int height)
        {
             var destRect = new Rectangle(0, 0, width, height);
             var destImage = new Bitmap(width, height);

             destImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);

             using (var graphics = Graphics.FromImage(destImage))
             {
                 graphics.CompositingMode = CompositingMode.SourceCopy;
                 graphics.CompositingQuality = CompositingQuality.HighQuality;
                 graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                 graphics.SmoothingMode = SmoothingMode.HighQuality;
                 graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;

                 using (var wrapMode = new ImageAttributes())
                 {
                     wrapMode.SetWrapMode(WrapMode.TileFlipXY);
                     graphics.DrawImage(image, destRect, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel, wrapMode);
                 }
             }
            return destImage;
        }

        public static string ConvertImageToBase64String()
        {
            Image image = Image.FromFile(Globals.PRED_PATH);
            var imageStream = new MemoryStream();
            image.Save(imageStream, ImageFormat.Jpeg);
            imageStream.Position = 0;
            var imageBytes = imageStream.ToArray();
            return Convert.ToBase64String(imageBytes);
        }
    }

函数调用：

ImageHandler.convertToFormat(FilePath);
string encodedImage = ImageHandler.ConvertImageToBase64String();

Answer 1

作为快速修复，您可以在方法 ConvertImageToBase64String 中的 image.Save(imageStream, ImageFormat.Jpeg); 之后添加 image.Dispose(); 以使其生效。

但是我建议您将 using 语句添加到 convertToFormat 和 ConvertImageToBase64String 以在使用后正确释放资源。

public static void convertToFormat(string filename)
{
    using (var image = Image.FromFile(@filename))
    {
        using (var bitmap = ResizeImage(image, Globals.ImageSize, Globals.ImageSize))
        {
            bitmap.Save(Globals.PRED_PATH, ImageFormat.Jpeg);
        }
    }
}

public static string ConvertImageToBase64String()
{
    using (var image = Image.FromFile(Globals.PRED_PATH))
    {
        using (var imageStream = new MemoryStream())
        {
            image.Save(imageStream, ImageFormat.Jpeg);
            imageStream.Position = 0;
            var imageBytes = imageStream.ToArray();
            return Convert.ToBase64String(imageBytes);
        }
    }
}

GDI+ System.Runtime.InteropServices.ExternalException 图像调整大小和转换

GDI+ System.Runtime.InteropServices.ExternalException On Image resize and conversion

c#

image

bitmap