HttpClient Post 方式 提交文件和参数（multipartform-data）

第一步：引入nuget包

Install-Package System.Net.Http

/// <summary> /// post 请求 /// </summary> /// <param name="url">请求地址</param> /// <param name="paramters">参数</param> /// <param name="file">文件</param> /// <returns></returns> public static string PostJsonFormData(string url, Dictionary<string, object> paramters, string file) { string result = ""; try { HttpClient client = new HttpClient(); var FormData = new MultipartFormDataContent(); string boundary = string.Format($",boundary=--{0}", DateTime.Now.Ticks.ToString("x")); FormData.Headers.Add("ContentType", $"multipart/form-data{boundary}"); if (!string.IsNullOrEmpty(file)) { string file_Type = "faceImage"; FormData.Add(new ByteArrayContent(File.ReadAllBytes(file)), file_Type, file); } foreach (var key in paramters.Keys) { FormData.Add(new StringContent(paramters[key].ToString()), key); } HttpResponseMessage response = client.PostAsync(url, FormData).Result; result = response.Content.ReadAsStringAsync().Result; } catch (Exception err) { return "PostJsonFormData Err:" + err.Message; } return result; }