首先，图片转化为字节流        public byte[] ImagefileToByte(string srcImagePath)        {            System.IO.MemoryStream m = new System.IO.MemoryStream();            System.Drawing.Bitmap bp = new System.Drawing.Bitmap(srcImagePath);            bp.Save(m,System.Drawing.Imaging.ImageFormat.Jpeg);            byte[] ImageByte = m.GetBuffer();            return ImageByte;        }最外层调用的方法        public string postUploadImage(string ImagePath)        {            string fileName = System.IO.Path.GetFileName(ImagePath);            byte[] fileDatas = upImg.ImagefileToByte(ImagePath);            Stream stream = new MemoryStream(fileDatas);            string uploadImageResult = CreatePostHttpRespone(uploadImageUrl, stream, "application/octet-stream");            return uploadImageResult;            //uploadImageUrl=http://gw.api.alibaba.com/openapi/param2/1/aliexpress.open/api.uploadImage/自己店铺的appkey?fileName=aa.jpg&_aop_signature=签名        }       public  string CreatePostHttpRespone(string url,Stream stream,string contentType)        {                if (string.IsNullOrEmpty(url))                {                    throw new ArgumentNullException("url");                }                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url) ;                request.Method = "POST";                request.Accept = "*/*";                request.KeepAlive = true;                request.ContentType = contentType;                request.Credentials = System.Net.CredentialCache.DefaultCredentials;                request.ContentLength = stream.Length;                using (Stream requestStream = request.GetRequestStream())                {                    //将内存流数据读取位置归零                    stream.Position = 0;                    byte[] tempBuffer = new byte[stream.Length];                    stream.Read(tempBuffer, 0, tempBuffer.Length);                    stream.Close();                    //将内存流中的buffer写入到请求写入流                    requestStream.Write(tempBuffer, 0, tempBuffer.Length);                    requestStream.Close();                    //获取到上传请求的响应                    WebResponse response = request.GetResponse();                    //获取到上传返回的数据                    //string html = GetResponseString(response);                    StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.UTF8);                    string content = reader.ReadToEnd();                    response.Close();                    request = null;                    return content;                }            }