POSTing JSON Object HTTPClient. Received Value is NULL WEB API ASP MVC

Question

I'm trying to post JSON data to web api, both projects run on my local machine.

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri(@"http://localhost:53818/");
    var result = client.PostAsync("api/values", new StringContent(data, Encoding.UTF8, "application/json")).Result;
    string resultContent = result.Content.ReadAsStringAsync().Result;
    Console.WriteLine(resultContent);
}

Received values in This post method is NULL

public HttpResponseMessage Post([FromBody]string value)
{
    return new HttpResponseMessage(HttpStatusCode.Created);
}

EDIT ----------- So I managed to figure out what the issue was. I've substituted this line of code

client.PostAsync("api/values", new StringContent(data, Encoding.UTF8, "application/json")).Result;

with the following and it worked, if someone will post the explanation I will be grateful

var response = client.PostAsJsonAsync("api/values", data).Result;

What does `data` look like from your first snippet (where you make the request)? — Jasen, May 19 '15 at 21:00
My data is a JSON file which is generated in another method and is passed to this one, data is generated correctly — mr. Holiday, May 19 '15 at 21:01
So is data named in a way that your WebAPI action signature will pick up with automatic binding? — Jasen, May 19 '15 at 21:04
@Jasen can you please explain in more details what do you mean? — mr. Holiday, May 19 '15 at 21:35

score 1 · Answer 1 · edited May 23 '17 at 12:32

1

This is becouse WebApi isn't good at serializing primitive types from the body, when you are sending the 'Content-Type' Header as application/json the framework is trying to serialize the content with the set Json serializer and isn't able, that's why you are getting null in the variable.

You can either

Change the type of the parameter from string to JToken or
Include a Media Type Formatter that handles plain text (see https://stackoverflow.com/a/29914360/1422608)

edited May 23 '17 at 12:32

Community

1
1

answered May 19 '15 at 21:05

evilpilaf

1,991
2
21
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I changed the type of the parameter to JToken but now StringContent is throwing an exception – mr. Holiday May 19 '15 at 21:19
@IliaAptsiauri what exception is it throwing? – evilpilaf May 19 '15 at 21:29
it says that no override method exists, I've tried to use data.toString() basically it's the same as it was and it didn't work – mr. Holiday May 19 '15 at 21:31
How to use `MediaTypeFormatter `? I've added to my application, can you let me know..how we can use it? – Hina Khuman Aug 29 '17 at 09:23

score 0 · Answer 2 · answered Jul 11 '16 at 15:50

0

Because you call values and your method expect value. Change your call to value or change the method signature for values which in this case would make more sense

answered Jul 11 '16 at 15:50

Marc Roussel

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POSTing JSON Object HTTPClient. Received Value is NULL WEB API ASP MVC

2 Answers2