C#图片下载

        #region

        private byte[] GetImageContent(string picName)

        {

            string fileURL = "http://localhost:/img/" + picName;

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(fileURL);

            request.AllowAutoRedirect = true;

            WebProxy proxy = new WebProxy();

            proxy.BypassProxyOnLocal = true;

            proxy.UseDefaultCredentials = true;

            request.Proxy = proxy;

            WebResponse response = request.GetResponse();

            using (Stream stream = response.GetResponseStream())

            {

                using (MemoryStream ms = new MemoryStream())

                {

                    Byte[] buffer = new Byte[1024];

                    int current = 0;

                    while ((current = stream.Read(buffer, 0, buffer.Length)) != 0)

                    {

                        ms.Write(buffer, 0, current);

                    }

                    return ms.ToArray();

                }

            }

        }

        private void WriteResponse(string picName, byte[] content)

        {

            Response.Clear();

            Response.ClearHeaders();

            Response.Buffer = false;

            Response.ContentType = "application/octet-stream";

            Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(picName, Encoding.Default));

            Response.AppendHeader("Content-Length", content.Length.ToString());

            Response.BinaryWrite(content);

            Response.Flush();

            Response.End();

        }

        #endregion



        protected void btt_Click(object sender, EventArgs e)

        {

            byte[] content = this.GetImageContent("Desert.jpg");

            this.WriteResponse("Desert.jpg", content);

        }