Net以WebAPI形式傳送fromData格式的資料上傳檔案，示例程式碼如下：

 public static async Task<HttpResponseMessage> HttpPostFileAsync(string url, BearerToken token, BillReconcileFileTenant billReconcile, string filePath)
        {
            using (var httpClient = new HttpClient() { BaseAddress = new Uri(baseAddress) })
            {
                httpClient.DefaultRequestHeaders.Accept.Clear();
                httpClient.DefaultRequestHeaders.Authorization
                           
 
= new AuthenticationHeaderValue("Bearer", token.access_token);
                using (Stream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
                {
                    MultipartFormDataContent formData = new MultipartFormDataContent();
                    formData.Add(
 
new StringContent(billReconcile.TenantName), "\"TenantName\"");// 使用"\"來轉義
                    formData.Add(new StringContent(billReconcile.BillDate), "\"BillDate\"");
                    formData.Add(new StringContent(billReconcile.Count.ToString()), "\"Count\"");
                    formData.Add(new
 
 StringContent(billReconcile.Amount.ToString()), "\"Amount\"");
                    formData.Add(new StreamContent(fileStream, (Int32)fileStream.Length), "Data", billReconcile.FileName);
                    HttpResponseMessage response = await httpClient.PostAsync(url, formData);
                    if (!response.IsSuccessStatusCode)
                    {
                        LogUtil.Error($"{DateTime.Now.ToString()}對賬介面對賬失敗，返回狀態碼為：{Convert.ToInt32(response.StatusCode)}");
                    }
                    else
                    {
                        LogUtil.Info($"{DateTime.Now.ToString()}對賬介面Post請求成功，返回狀態碼為：{Convert.ToInt32(response.StatusCode)}");
                    }
                    return response;
                }
            }
        }

注意：BaseAddress和url使用時是BaseAddress+url為請求地址再去使用。