這個(gè)一直研究了很久，通過(guò)json字符串解析成鍵值對(duì)，再添加到Http請(qǐng)求中，經(jīng)過(guò)測(cè)試可以正常接收數(shù)據(jù)。
封裝了方法

       public string HttpPost(string url, string jsonStr)
        {
            string content = "";
            try
            {
                string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
                byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
                byte[] endbytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");

                HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
                request.ContentType = "multipart/form-data; boundary=" + boundary;
                request.Method = WebRequestMethods.Http.Post;
                request.KeepAlive = true;
                request.Timeout = -1;

                CredentialCache credentialCache = new CredentialCache();
                credentialCache.Add(new Uri(url), "Basic", new NetworkCredential("member", "secret"));
                request.Credentials = credentialCache;

                request.ServicePoint.Expect100Continue = false;
                Dictionary<string, string> map = JsonStringToKeyValuePairs(jsonStr);
                using (Stream stream = request.GetRequestStream())
                {
                    //1.1 key/value
                    string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
                    if (map != null)
                    {
                        foreach (string key in map.Keys)
                        {
                            stream.Write(boundarybytes, 0, boundarybytes.Length);
                            string formitem = string.Format(formdataTemplate, key, map[key]);
                            byte[] formitembytes = Encoding.GetEncoding("UTF-8").GetBytes(formitem);
                            stream.Write(formitembytes, 0, formitembytes.Length);
                        }
                    }
                    stream.Write(endbytes, 0, endbytes.Length);
                }
                //2.WebResponse
                HttpWebResponse response = request.GetResponse() as HttpWebResponse;
                using (Stream responsestream = response.GetResponseStream())
                {
                    using (StreamReader sr = new StreamReader(responsestream))
                    {
                        content = sr.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            {
                content =  ex.Message ;
            }
            return content;
        }
        public static Dictionary<string, string> JsonStringToKeyValuePairs(string jsonStr)
        {
            char jsonBeginToken = '{';
            char jsonEndToken = '}';

            if (string.IsNullOrEmpty(jsonStr))
            {
                return null;
            }
            //驗(yàn)證json字符串格式
            if (jsonStr[0] != jsonBeginToken || jsonStr[jsonStr.Length - 1] != jsonEndToken)
            {
                throw new ArgumentException("非法的Json字符串!");
            }

            var resultDic = new Dictionary<string, string>();
            var jobj = JObject.Parse(jsonStr);
            JsonOn(jobj, resultDic);
            return resultDic;
        }
        private static Dictionary<string, string> JsonOn(JToken jobT, Dictionary<string, string> Dic)
        {

            //找出包含嵌套的字段列
            if (jobT is JObject jobj && jobj.Properties().Count() > 0)
            {
                foreach (var item in jobj.Properties())
                {
                    JsonProperties(item, Dic);
                }
            }
            else
            {
                Dic.Add(jobT.Path, jobT.ToString());

                return Dic;
            }
            return Dic;
        }
        private static Dictionary<string, string> JsonProperties(JProperty jobj, Dictionary<string, string> Dic)
        {
            return JsonOn(jobj.Value, Dic);
        }

還有另一種簡(jiǎn)單的方法文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-514152.html

        public string HttpPost(string urlStr, string jsonStr)
        {
            string content = "";
            try
            {
                Dictionary<string, string> map = JsonStringToKeyValuePairs(jsonStr);

                var mfdc = new System.Net.Http.MultipartFormDataContent();
                mfdc.Headers.Add("ContentType", "multipart/form-data");//聲明頭部
                foreach (string key in map.Keys)
                {
                    mfdc.Add(new System.Net.Http.StringContent(map[key]), key);//參數(shù), 內(nèi)容在前,參數(shù)名稱在后
                }
                var clientTask = new System.Net.Http.HttpClient().PostAsync(urlStr, mfdc);//發(fā)起異步請(qǐng)求
                clientTask.Wait();//等待請(qǐng)求結(jié)果
                if (clientTask.Result.IsSuccessStatusCode)
                {
                    //請(qǐng)求正常
                    var resultTask = clientTask.Result.Content.ReadAsStringAsync();//異步讀取返回內(nèi)容
                    resultTask.Wait();//等讀取返回內(nèi)容
                    content = resultTask.Result;//返回內(nèi)容字符串
                }
                else
                {
                    //請(qǐng)求異常
                    content = "失敗";
                }
            }
            catch (Exception ex)
            {
                content = ex.Message;
            }
            return content;
        }

到了這里，關(guān)于c#HTTP使用form-data發(fā)送請(qǐng)求的文章就介紹完了。如果您還想了解更多內(nèi)容，請(qǐng)?jiān)谟疑辖撬阉鱐OY模板網(wǎng)以前的文章或繼續(xù)瀏覽下面的相關(guān)文章，希望大家以后多多支持TOY模板網(wǎng)！