无法在 ASP.NET 中使用 WebClient 下载图像

Question

在其中一个移动站点中，我创建了一个网页，其中我使用 webclient 从主站点（移动主站点）下载图像并使用位图调整大小，并将图像获取到移动站点，主站点的图像路径工作正常，但是当我使用 WebClient 下载图像以调整大小时，我收到以下错误：

CreateThumbnail :System.Net.WebException: Unable to connect to the
   remote server ---> System.Net.Sockets.SocketException: A connection
   attempt failed because the connected party did not properly respond
   after a period of time, or established connection failed because
   connected host has failed to respond 209.59.186.108:80 at
   System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot,
   SocketAddress socketAddress) at
   System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure,
   Socket s4, Socket s6, Socket& socket, IPAddress& address,
   ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout,
   Exception& exception)

任何人都可以建议任何解决此问题的方法，我尝试使用以下命令 ping 上述 IP (209.59.186.108)：

ping m.keyboardmag.com

它返回以下结果：

Pinging m.keyboardmag.com [209.59.186.108] with 32 byte
Reply from 209.59.186.108: bytes=32 time=233ms TTL=112
Reply from 209.59.186.108: bytes=32 time=237ms TTL=112
Reply from 209.59.186.108: bytes=32 time=230ms TTL=112
Reply from 209.59.186.108: bytes=32 time=231ms TTL=112

仍然无法使用 WebClient 连接和下载图像...

*************更新的代码片段******** ********

if (Request.QueryString["file"] != null)
        {
            string file = Request.QueryString["file"].ToString();
            int lnHeight = Convert.ToInt32(Request.QueryString["height"]);
            int lnWidth = Convert.ToInt32(Request.QueryString["width"]);
            string imgUrl = Request.QueryString["file"].ToString();
            Bitmap bmpOut = null;
            try
            {
                Bitmap loBMP;
                WebClient wb = new WebClient();

                byte[] ret = wb.DownloadData(imgUrl);

                MemoryStream ms = new MemoryStream(ret);
                loBMP = new Bitmap((Stream)ms);
                System.Drawing.Imaging.ImageFormat loFormat = loBMP.RawFormat;
                decimal lnRatio;
                int lnNewWidth = 0;
                int lnNewHeight = 0;
                //-----If the image is smaller than a thumbnail just return it As it is----- 
                if ((loBMP.Width < lnWidth && loBMP.Height < lnHeight))
                {
                    lnNewWidth = loBMP.Width;
                    lnNewHeight = loBMP.Height;
                }
                if ((loBMP.Width > loBMP.Height))
                {
                    lnRatio = (decimal)lnHeight / loBMP.Height;
                    lnNewHeight = lnHeight;
                    decimal lnTemp = loBMP.Width * lnRatio;
                    lnNewWidth = (int)lnTemp;
                    if (lnNewWidth > 128)
                    {
                        lnNewWidth = 128;
                    }
                    /*
                    lnRatio = (decimal)lnWidth / loBMP.Width;
                    lnNewWidth = lnWidth;
                    decimal lnTemp = loBMP.Height * lnRatio;
                    lnNewHeight = (int)lnTemp;*/
                }
                else
                {
                    lnRatio = (decimal)lnHeight / loBMP.Height;
                    lnNewHeight = lnHeight;
                    decimal lnTemp = loBMP.Width * lnRatio;
                    lnNewWidth = (int)lnTemp;
                    if (lnNewWidth < 75)
                    {
                        lnNewWidth = 75;
                    }
                }
                bmpOut = new Bitmap(lnNewWidth, lnNewHeight);
                Graphics g = Graphics.FromImage(bmpOut);
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight);
                if (Path.GetExtension(imgUrl) == "jpg")
                    Response.ContentType = "image/jpeg";
                else if (Path.GetExtension(imgUrl) == "bmp")
                    Response.ContentType = "image/bmp";
                else if (Path.GetExtension(imgUrl) == "png")
                    Response.ContentType = "image/png";
                else if (Path.GetExtension(imgUrl) == "gif")
                    Response.ContentType = "image/gif";

                bmpOut.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (Exception ex)
            {
                HttpContext.Current.Response.Write("CreateThumbnail :" + ex.ToString());
            }
            finally
            {
            }

Answer 1

你能发布一些示例代码吗？

过去我使用过以下代码，但从未遇到过任何问题。

WebClient wb = new WebClient();
Image originalImage = Image.FromStream(wb.OpenRead(Url));
Image thumbNail = ImageResize.Crop(originalImage, Width, Height, ImageResize.AnchorPosition.Top);

图片保存代码：

EncoderParameter qualityParam = new EncoderParameter(Encoder.Quality, MyQuality);
ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");
EncoderParameters encoderParams = new EncoderParameters(1);
encoderParams.Param[0] = qualityParam;
originalImage.Save(FilePath, jpegCodec, encoderParams);

MyQuality 是一个介于 0-100 之间的整数。 50-70 是一个很好的起点，具体取决于您的需要。

Answer 2

您的移动网站响应时间过长。您显然正在访问端口 80（从您的 sn-p 可以看出），因此如果您可以使用浏览器访问您的站点，那么您的代码没有任何问题。您有某种网络延迟问题。

以防万一，这样做：

WebClient.DownloadFile("UrlToImage");

应该可以正常工作。