Error sending json in POST to web API service

Question

I'm creating a web service using Web API. I implemented a simple class

public class ActivityResult {     public String code;     public int indexValue;     public int primaryCodeReference; } 

And then I have implemented inside my controller

[HttpPost] public HttpResponseMessage Post(ActivityResult ar) {     return new HttpResponseMessage(HttpStatusCode.OK); } 

But when I call the API passing in POST the file json:

{"code":"XXX-542","indexValue":"3","primaryCodeReference":"7"} 

I obtain the following error message:

{     "Message": "The request entity's media type 'text/plain' is not supported for this resource.",     "ExceptionMessage": "No MediaTypeFormatter is available to read an object of type 'ActivityResult' from content with media type 'text/plain'.",     "ExceptionType": "System.Net.Http.UnsupportedMediaTypeException",     "StackTrace": "   in System.Net.Http.HttpContentExtensions.ReadAsAsync[T](HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   in System.Net.Http.HttpContentExtensions.ReadAsAsync(HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   in System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)" } 

What am I doing wrong?

Answer 1

In the HTTP request you need to set Content-Type to: Content-Type: application/json

So if you're using fiddler client add Content-Type: application/json to the request header