优化代码，使用using块 参考 public bool SaveCheckPicture(string path, string fileName, Image img, int dpi = 600, int maxWidth = 0, int maxHeight = 0,out string msg ) { msg = string.Empty; try { // 计算缩放比例 float scale = (float)dpi / img.HorizontalResolution; // 计算缩放后的尺寸 int width = (int)(img.Width * scale); int height = (int)(img.Height * scale); // 如果指定了最大宽度或最大高度，则按比例缩放 //if (maxWidth > 0 && width > maxWidth) //{ // height = (int)(height * ((float)maxWidth / width)); // width = maxWidth; //} //if (maxHeight > 0 && height > maxHeight) //{ // width = (int)(width * ((float)maxHeight / height)); // height = maxHeight; //} // 创建缩放后的位图 Bitmap bmp = new Bitmap(width, height); // 设置位图的DPI bmp.SetResolution(dpi, dpi); // 创建绘图对象 Graphics g = Graphics.FromImage(bmp); g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; // 绘制缩放后的图片 g.DrawImage(img, new Rectangle(0, 0, width, height)); // 保存缩放后的图片 //bmp.Save(Path.Combine(path, fileName), System.Drawing.Imaging.ImageFormat.Jpeg); MemoryStream stream = new MemoryStream(); bmp.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg); byte[] data = stream.ToArray(); // 释放资源 stream.Dispose(); g.Dispose(); bmp.Dispose(); img.Dispose(); return SaveCheckPicture(path, fileName, data, out msg); // return true; } catch (Exception ex) { msg = ex.ToString(); return false; } }

可以使用 using 块来自动释放资源，同时对代码进行优化，如下所示：

public bool SaveCheckPicture(string path, string fileName, Image img, int dpi = 600, int maxWidth = 0, int maxHeight = 0, out string msg)
{
    msg = string.Empty;
    try
    {
        // 计算缩放比例
        float scale = (float)dpi / img.HorizontalResolution;
        // 计算缩放后的尺寸
        int width = (int)(img.Width * scale);
        int height = (int)(img.Height * scale);
        // 如果指定了最大宽度或最大高度，则按比例缩放
        //if (maxWidth > 0 && width > maxWidth)
        //{
        //    height = (int)(height * ((float)maxWidth / width));
        //    width = maxWidth;
        //}
        //if (maxHeight > 0 && height > maxHeight)
        //{
        //    width = (int)(width * ((float)maxHeight / height));
        //    height = maxHeight;
        //}
        // 创建缩放后的位图
        using (Bitmap bmp = new Bitmap(width, height))
        {
            // 设置位图的DPI
            bmp.SetResolution(dpi, dpi);
            // 创建绘图对象
            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                // 绘制缩放后的图片
                g.DrawImage(img, new Rectangle(0, 0, width, height));
                // 保存缩放后的图片
                using (MemoryStream stream = new MemoryStream())
                {
                    bmp.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
                    byte[] data = stream.ToArray();
                    // 释放资源
                    img.Dispose();
                    return SaveCheckPicture(path, fileName, data, out msg);
                }
            }
        }
    }
    catch (Exception ex)
    {
        msg = ex.ToString();
        return false;
    }
}

这样可以自动释放资源，避免手动释放时出现异常。