C# 返回图片的字节流byte[]

最新推荐文章于 2024-02-05 13:16:04 发布

转载最新推荐文章于 2024-02-05 13:16:04 发布 · 351 阅读

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CC 4.0 BY-SA版权

原文链接：https://yq.aliyun.com/articles/54968

本文介绍了一种从URL或本地路径获取图片并将其转换为字节流的高效方法，包括使用WebClient和自定义函数实现。通过判断图片来源，采用不同的读取策略以提高性能。

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#region 返回图片的字节流byte[]
        /// <summary>
        /// 返回图片的字节流byte[]
        /// </summary>
        /// <param name="imagePath"></param>
        /// <param name="webClient"></param>
        /// <returns></returns>
        public static byte[] getImageByte(string imagePath, WebClient webClient)
        {
            byte[] imgByte = null;
            try
            {
                //MessageBox.Show("getImageByte");
                //Stopwatch stopwatch = new Stopwatch();
                //stopwatch.Start();
                //DateTime dateStart = DateTime.Now;

                if (PubFunc.UrlDiscern(imagePath))
                {
                    Bitmap bt = new Bitmap(webClient.OpenRead(imagePath));
                    imgByte = PubFunc.ImgToByte(bt);
                }
                else
                {
                    using (FileStream files = new FileStream(imagePath, FileMode.Open))
                    {
                        imgByte = new byte[files.Length];
                        files.Read(imgByte, 0, imgByte.Length);
                        files.Close();
                    }
                }
                //stopwatch.Stop();
                //MessageBox.Show((DateTime.Now - dateStart).TotalMilliseconds.ToString());

            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.ToString());
            }
            return imgByte;
        }
        #endregion

  #region 图片转换成字节流
        /// <summary>
        /// 图片转换成字节流
        /// </summary>
        /// <param name="img">要转换的Image对象</param>
        /// <returns>转换后返回的字节流</returns>
        public static byte[] ImgToByte(Image img)
        {
            try
            {
                using (MemoryStream ms = new MemoryStream())
                {
                    byte[] imagedata = null;
                    img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                    imagedata = ms.GetBuffer();
                    return imagedata;
                }
            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.ToString());
                return null;
            }
        }
        #endregion