base64编码的字符串与图片相互转换

         #region 图片转为base64编码的字符串---ImgToBase64String
         /// <summary>
         /// 图片转为base64编码的字符串
         /// </summary>
         /// <param name="Imagefilename">图片地址</param>
         /// <returns></returns>
         public static List<publicAnnex> ImgToBase64String(string Imagefilename)
         {
             try
             {
                 var AList = new List<publicAnnex>();
                 var Listarr = Imagefilename.Split(',');
                 foreach (var item in Listarr)
                 {
                     string uppath = System.Web.HttpContext.Current.Server.MapPath(item);
                     Bitmap bmp = new Bitmap(uppath);
                     MemoryStream ms = new MemoryStream();
                     bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                     byte[] arr = new byte[ms.Length];
                     ms.Position = ;
                     ms.Read(arr, , (int)ms.Length);
                     ms.Close();
                     var A = new publicAnnex();
                     A.Content = Convert.ToBase64String(arr);
                     AList.Add(A);
                 }
                 return AList;
             }
             catch (Exception ex)
             {
                 return null;
             }
         }
         #endregion

         #region base64编码的字符串转为图片---Base64StringToImage
         /// <summary>
         /// base64编码的字符串转为图片
         /// </summary>
         /// <param name="strbase64">字符串</param>
         /// <returns></returns>
         public static string Base64StringToImage(List<string> strbase64)
         {
             try
             {
                 var AnnexAddress = "";
                 foreach (var item in strbase64)
                 {
                     string time = DateTime.Now.ToString("yyyyMMddHHmmssffff");
                     byte[] arr = Convert.FromBase64String(item);
                     MemoryStream ms = new MemoryStream(arr);
                     Bitmap bmp = new Bitmap(ms);
                     string uppath = System.Web.HttpContext.Current.Server.MapPath("~/UploadFiles/Image/") + "YMD_" + time + ".jpg";
                     bmp.Save(uppath);
                     ms.Close();
                     AnnexAddress += "/UploadFiles/Image/YMD_" + time + ".jpg,";
                 }
                 AnnexAddress.Substring(, AnnexAddress.Length - );
                 return AnnexAddress;
             }
             catch (Exception ex)
             {
                 return null;
             }
         }
         #endregion