后端模拟网页表单提交数据

　　　　　/// <summary>
        /// 后端模拟网页表单提交数据
        /// </summary>
        /// <returns></returns>
        public string TestFormPost()
        {
            using (HttpClient client = new HttpClient())
            {
                using (var content = new MultipartFormDataContent())
                {
                    //字段
                    NameValueCollection nvCollect = new NameValueCollection();
                    nvCollect.Add("Parameter", "这是普通值");
                    var parameter = new List<ByteArrayContent>();
                    foreach (var key in nvCollect.AllKeys)
                    {
                        var dataContent = new ByteArrayContent(Encoding.UTF8.GetBytes(nvCollect[key]));
                        dataContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                        {
                            Name = key
                        };
                        parameter.Add(dataContent);
                    };

                    //文件
                    var file = new List<ByteArrayContent>();
                    new ByteArrayContent(System.Text.Encoding.Default.GetBytes("文本文件内容")).Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                    {
                        FileName = "LogFileName.txt"
                    };

                    var aciont = new Action<List<ByteArrayContent>>((parameterData) =>
                    {
                        foreach (var param in parameterData)
                        {
                            file.Add(param);
                        }
                    });

                    //拼接表单值
                    aciont(parameter);
                    aciont(file);

                    var responseResult = client.PostAsync("地址" + "/api", content).Result;

                    return responseResult.Content.ReadAsStringAsync().Result;//线程异步结果
                }
            }
        }

原文地址：https://www.cnblogs.com/liyiboke/p/10000245.html