读取图片数据流转换成图片

  string imgUrl = "http://www.scapex.cn/upload/201601/28/201601280915393586.jpg";
            if (!string.IsNullOrEmpty(imgUrl))
            {
                WebRequest webRequest = WebRequest.Create(new Uri(imgUrl));
                WebResponse webResponse = webRequest.GetResponse();
                Stream stream = webResponse.GetResponseStream();
                byte[] bytes = new byte[stream.Length];
                stream.Read(bytes, 0, bytes.Length);
                stream.Seek(0, SeekOrigin.Begin);
                string str = new System.Text.UnicodeEncoding().GetString(bytes);
                
                stream.Close();
                webResponse.Close();


                Bitmap myImage = new Bitmap(webResponse.GetResponseStream());

                MemoryStream ms = new MemoryStream();
                myImage.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                Response.ClearContent();
                Response.ContentType = "image/Jpeg";
                Response.BinaryWrite(ms.ToArray());
}

读取文件转换成BaseCode  

if (!File.Exists(filePath)) return baseCode;
            using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                byte[] bytes = new byte[fs.Length];
                fs.Read(bytes, 0, bytes.Length);
                baseCode = Convert.ToBase64String(bytes);
            }

BaseCode保存文件

  if (!Directory.Exists(filePath))
                {
                    Directory.CreateDirectory(filePath);
                }
                byte[] bytes = Convert.FromBase64String(model.BaseCode);
                using (Stream fs = new FileStream(model.FilePath, FileMode.Create))
                {
                    fs.Write(bytes, 0, bytes.Length);
                }

 public static string GetBaseCode(string filePath)
        {
            string base64 = string.Empty;
            if (string.IsNullOrEmpty(filePath)) return base64;

            HttpWebRequest webrequest = (HttpWebRequest)HttpWebRequest.Create(filePath);
            HttpWebResponse response = (HttpWebResponse)webrequest.GetResponse();
            try
            {
                using (Stream stream = response.GetResponseStream())
                {
                    using (BinaryReader reader = new BinaryReader(stream))
                    {
                        byte[] arr = reader.ReadBytes(1024 * 500);
                        base64 = Convert.ToBase64String(arr);
                    }
                }
                response.Close();
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            finally
            {
                response.Dispose();
            }
            return base64;
        }