如何在 Web 客户端请求中检索自定义错误消息？

Question

Server side code to return file

[HttpGet]
public HttpResponseMessage GetVersionList(string Credentials, string VersionNumber)
{
  try
  {
      string UserLoginStatus = objUtility.LoginUser(objUtility.GetUserName(Credentials), objUtility.GetPassWord(Credentials));

      if (UserLoginStatus == "OK")
      {
          var path = objUtility.GetFileName(VersionNumber);

          if (path != null)
          {
              return FileAsAttachment(path, VersionNumber + ".exe");
          }
          else
          {               
              return Request.CreateErrorResponse(HttpStatusCode.OK, "File Not Found.");
          }
      }
      else
      {
          // Return reason why it failed.
          // It could be not authorized user, Not Active user, UID/Password wrong etc. 
          // Store into UserLoginStatus variable and pass show to client
          return Request.CreateResponse<string>(HttpStatusCode.OK, UserLoginStatus);
      }
  }
  catch (System.Exception ex)
  {
      return Request.CreateResponse<string>(HttpStatusCode.OK, ex.Message);
  }

}

// Win app code to download file 
using (WebClient webClient = new WebClient())
{  
            try
            {
                webClient.DownloadFile(serverUrl, (txtPath.Text + "\" + txtVersion.Text + ".exe"));
            }
            catch (WebException wex)
            {
                // Show error message here 
            }
        }
    }
    catch (Exception ex)
    {
        lblStatus.Text = ex.InnerException + " <br> " + ex.Message;
    }
}

Answer 1

我最近为POS写的休息服务就是这样做的。 （myErrorType 只是你实际使用的 class 的虚拟对象...）

using (var response = request.GetResponse())
                {   
 using (var reader = new StreamReader(response.GetResponseStream()))
                            {
                                var reply = reader.ReadToEnd();
                                myErrorType result = Newtonsoft.Json.JsonConvert.DeserializeObject<myErrorType>(reply);
                                return result.Status;
                                // do something with the results
                            }
}

抛出自定义错误：

myErrorType  errresponse = new myErrorType();//dummy class, create your own...
throw new WebFaultException<myErrorType>(errresponse, HttpStatusCode.BadRequest);