调用Odata Service Put方法C＃

Question

我正在尝试使用PUT方法使用Odata服务更新记录。以下是执行此操作的代码

 private async Task<HttpResponseMessage> PutJsonAsync(string messageBody,string B_Code)
 {
 string userName = ConfigurationManager.AppSettings["Username"];
 string password = ConfigurationManager.AppSettings["Password"];
 string BaseURL = ConfigurationManager.AppSettings["BaseURL"];

 try
 {
   using (var httpClient = new HttpClient())
   {
       var request = new StringContent(messageBody, Encoding.UTF8, "application/json");
       string apiUrl = "SAM('" + B_Code + "')";
       request.Headers.ContentType = new MediaTypeHeaderValue("application/json");
       request.Headers.TryAddWithoutValidation("If-Match", "*");
       var url = string.Format("{0}{1}", BaseURL, apiUrl);
       var creds = userName + ":" + password;
       var credentials = Encoding.ASCII.GetBytes(creds);
       httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(credentials));

       response = await httpClient.PutAsync(new Uri(url), request);
   }
  }
 catch (Exception ex)
 {
   throw ex;
 }
 return response;
  }

我正在设置标头If-Match，这个PUT方法需要工作。 但是当我调试它时会在响应中抛出错误响应501

response {StatusCode: 501, ReasonPhrase: 'Not Implemented', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
OData-Version: 4.0 Date: Mon, 30 Oct 2017 20:42:28 GMT Set-Cookie: JSESSIONID=XYZ; Path=/; Secure; HttpOnly Set-Cookie: XYZ;PATH=/;SECURE;HTTPONLY Server: Apache-Coyote/1.1 Vary: Accept-Encoding Connection: keep-alive Content-Length: 277 Content-Type: application/json; odata.metadata=minimal }} System.Net.Http.HttpResponseMessage

但是在POSTMAN中尝试相同的PUT方法可以正常工作而不会出现任何错误。验证了messageBody是有效的JSON。不确定可能是什么问题。