C# 上传excel 文件

            Excel.Workbook wbk = this.application.Workbooks[1];
            String copyf = String.Format("./{0}.xlsx", DateTime.Now.ToString("yyyy-MM-dd'T'HH.mm.ssZ"));
            wbk.SaveCopyAs(copyf);
            MessageBox.Show(copyf);
            //wbk.Save();
            // 读取文件
            Stream fileStream = new FileStream(@copyf, FileMode.Open, FileAccess.Read);
            // 实例化multipart表单模型
            var formData = new MultipartFormDataContent();
            // 设定文本类型表单项，使用StringContent存放字符串
            formData.Add(new StringContent("example.xlsx"), "file");
            // 设定文件类型表单项，使用StreamContent存放文件流
            formData.Add(new StreamContent(fileStream), "file", "example.xlsx");

            // 实例化HttpClient
            HttpClient client = new HttpClient();
            // 发送请求
            HttpResponseMessage result = client.PostAsync("http://localhost:3000/pupload", formData).Result;
            // 接受结果
            string responseResult = result.Content.ReadAsStringAsync().Result;
            // 打印结果
            Console.WriteLine(responseResult);
            client.Dispose();
            fileStream.Close();