c# webservice return error

Question

I need some help regarding this. Please be gentle with me, Im not an expert - yet.

The thing is that Im trying to send data from a client (browser) to the server (webservice) via JSON. When I watch the POST data in Fiddler, I can see the JSON I send. This is valid (tested). But my webservice, (when I manually test then I get a return OK), returns the following: "{"Message":"There was an error processing the request.","StackTrace":"","ExceptionType":""}"

Unfortunately its only for internal use so I can't publish the webservice for you.

Can someone explain to me whats wrong?

1.) Javascript code:

<script>
  var markers = "{param1:1, param2:\"test\"}";

    $.ajax({
        type: "POST",
        url: "http://xxx.xxx.xxx.xxx/site/util.asmx/CreateMarkers",
        // The key needs to match your method's input parameter (case-sensitive).
        data: JSON.stringify({ Markers: markers }),
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (data) { alert(data); },
        failure: function (errMsg) {
            alert(errMsg);
        }
       });
</script>

2.) asmx code

<%@ WebService Language="C#" Class="site.Util" %>
using System;
using System.Web.Services;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Services;

namespace site{

[WebService(Namespace="http://xxx.xxx.xxx.xxx/site/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

public class Util: WebService
{    
  [WebMethod]
  [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
  public string CreateMarkers(int param1, string param2)
  {
    return "OK";
  }
}

Try without stringifying: data: markers, ... It looks like your data is already json format with matching up parameters for param1, param2. You don't want a root Markers property. — Andez
– Andez, Commented Feb 3, 2017 at 10:39
You can also try using an app such as Postman (getpostman.com) to test your web service API. It is available standalone or as a plugin to browsers. It allows you to test the pure API to send and receive data, so you can be sure that what you send and receive is as expected — jason.kaisersmith
– jason.kaisersmith, Commented Feb 3, 2017 at 10:44
@Andez Thanks, but without your modification this is what I can see in fiddler: {"Markers":"{param1:1, param2:\"test\""} I assume this part is correct if I change it as you suggest then I get {param1:1, param2:"test"} which is not valid JSON. It might be me that doesn't understand this correct. Can you help me further? — Lars Hansen
– Lars Hansen, Commented Feb 3, 2017 at 10:52

Nkosi · Accepted Answer · 2017-02-03 10:44:49Z

1

Try formatting the data sent to match the web service method

<script>
    var markers = {param1:1, param2:"test"}; //<-- format the model

    $.ajax({
        type: "POST",
        url: "http://xxx.xxx.xxx.xxx/site/util.asmx/CreateMarkers",
        // The key needs to match your method's input parameter (case-sensitive).
        data: JSON.stringify(markers),  //<-- just send the markers
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (data) { alert(data); },
        failure: function (errMsg) {
            alert(errMsg);
        }
   });
</script>

answered Feb 3, 2017 at 10:44

Nkosi

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5 Comments

Nkosi Over a year ago

in answer above, markers is stringified before sending. in script code var markers is a javascript object not JSON, hence the reason it is stringified before sending. what do you see in fiddler when using the above suggestion?

Lars Hansen Over a year ago

This must be it. you are the second to indicate this way to solve the problem. But how am I to send a json without a root(markers) and still have a vailid json? I have modified the asmx so that it only has one type string in the signature. And then altering the script to var markers ="[ \"Ford\", \"BMW\", \"Fiat\"]"; But still the same error

Lars Hansen Over a year ago

Then I see this in fiddler: [ "Ford", "BMW", "Fiat"]. The reply from the webservice is still: {"Message":"There was an error processing the request.","StackTrace":"","ExceptionType":""}

Nkosi Over a year ago

changing up the question like this is going to make it confusing and more difficult to understand what is the problem. Provide a minimal reproducible example that can be used to reproduce the issue. I under stand the sensitive nature of not wanting to expose internal code but without a clear picture of the issue I doubt you will get proper help with out it.

Nkosi Over a year ago

@LarsHansen I suggest putting break points in your code and debugging where the error is being thrown.

Brobic Vripiat · Accepted Answer · 2019-09-26 19:10:28Z

0

I had the same problem and solved it with this in web.config:

<customErrors mode="Off" />

After that change, Message, ExceptionType, and Stack trace became properly populated instead of the standard "There was an error processing the request." which gets returned for all exceptions when mode=on and is not very helpful for debugging or reporting.

answered Sep 26, 2019 at 19:10

Brobic Vripiat

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