(HttpWebResponse)request.GetResponse()报错，必须先将 ContentLength 字节写入请求流，再调用...

[hn_tzy]

try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(“https://honors.libraries.psu.edu/browse/author/all/”);
                request.CookieContainer = new CookieContainer();
                CookieContainer cookie = request.CookieContainer;//如果用不到Cookie，删去即可

                //以下是发送的http头，随便加，其中referer挺重要的，有些网站会根据这个来反盗链
                request.Referer = "https://honors.libraries.psu.edu/browse/author/all/";
                request.Accept = "text/html, application/xhtml+xml, */*";                
                request.Headers["Accept-Language"] = "en-US";                
                request.UserAgent = "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)";
                request.Headers["UA-CPU"] = "AMD64";
                request.Headers["Accept-Encoding"] = "gzip, deflate";
                request.Headers["Cache-Control"] = "no-cache";
                request.KeepAlive = true;
                //上面的http头看情况而定，但是下面俩必须加
                request.ContentType = "application/x-www-form-urlencoded";
                request.Method = "POST";
                request.Host = "honors.libraries.psu.edu";

                Encoding encoding = Encoding.UTF8;//根据网站的编码自定义
                string[] keys = dicParam.Keys.ToArray<string>();
                string[] values = dicParam.Values.ToArray<string>();
                int iCount = dicParam.Count;
                string postDataStr = "";
                for (int i = 0; i < iCount; i++)
                {
                    postDataStr += keys[i] + "=" + values[i] + "&";
                }
                if (postDataStr.Length > 0)
                {
                    postDataStr = postDataStr.Substring(0, postDataStr.Length - 1);
                }
                byte[] postData = encoding.GetBytes("csrfmiddlewaretoken=04696113ff3ee3e8220dd9044921e100&browse_start=all&browse_type=author&page=2&display=50&num_display_items=50");//postDataStr即为发送的数据，格式还是和上次说的一样
                request.ContentLength = postData.Length*2;
                Stream requestStream = request.GetRequestStream();
                requestStream.Write(postData, 0, postData.Length);

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream responseStream = response.GetResponseStream();
                //如果http头中接受gzip的话，这里就要判断是否为有压缩，有的话，直接解压缩即可
                if (response.Headers["Content-Encoding"] != null && response.Headers["Content-Encoding"].ToLower().Contains("gzip"))
                {
                    responseStream = new GZipStream(responseStream, CompressionMode.Decompress);
                }

                StreamReader streamReader = new StreamReader(responseStream, encoding);
                string retString = streamReader.ReadToEnd();

                streamReader.Close();
                responseStream.Close();
                return retString;
            }
            catch(Exception exp)
            {
                MessageBox.Show(exp.Message);
                return "";
            }     

执行到HttpWebResponse response = (HttpWebResponse)request.GetResponse();时报错：
"必须先将 ContentLength 字节写入请求流，然后再调用 [Begin]GetResponse。"

求解决，谢谢！

[save4me]

你request.ContentLength = postData.Length*2;为什么要将长度乘以2？而你requestStream.Write(postData, 0, postData.Length)写入的是postData.Length，即程序会认为request还没有写完，改成request.ContentLength = postData.Length

[hn_tzy]

没有乘以2也是一样的