Cannot post object from .net Client web-api web service - asp.net

Question

I have one .net client which tries to make http request to web api service
here is my Request:
public List<Category> GetCategories()
{
HttpClient client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:54558/");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
Task<string> response = client.GetStringAsync("api/CategoryApi/");
List<Category> lstCategory = JsonConvert.DeserializeObjectAsync<List<Category>>(response.Result).Result;
return lstCategory;
}
public void Create(Category category)
{
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var stringContent = new StringContent(category.ToString());
HttpResponseMessage responseMessage = client.PostAsync("api/CategoryApi/", stringContent).Result;
}
and in my webapi
public IEnumerable<Category> GetCategories()
{
return categoryRepository.data;
}
public string PostCategory(Category category)
{
categoryRepository.add(category);
return "MessageOk";
}
SO when I make request to my GetCategories action of the web-api everything is OK.
and no matter what I do it seems that .net application cannot find the Post action of the web-api and I never actually see entering in Postcategory method
as I have also put breakpoints here.
I only get the error
atusCode: 500, ReasonPhrase: 'Internal Server Error', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Pragma: no-cache
X-SourceFiles: =?UTF-8?B?QzpcVXNlcnNccG9zdGdyZXNcRGVza3RvcFxXZWJBcGlTZXJ2aWNlXFdlYkFwaVNlcnZpY2VcYXBpXENhdGVnb3J5QXBpXA==?=
Cache-Control: no-cache
Date: Sat, 13 Jun 2015 17:55:16 GMT
Server: Microsoft-IIS/8.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Content-Length: 1022
Content-Type: application/json; charset=utf-8
Expires: -1
}}
What may be the issue. Thak you in advance

Answer 1

You are posting just a Category.ToString which if you didn't override ToString to be a Json or XML string, it will fail on the server side because there is no way to deserialize the content into a Category object. You should serialize the Category on the client before posting it. Also make sure your request headers include the proper Content-Type of application/json. By posting StringContent, the Content-Type won't be application/json. You are setting the Accept header, but that only describes the data coming back to your client, not the data you are posting. One last thing, I would not use the same HttpClient for both the get and the post request. Each method should use it's own HttpClient so you don't have any extra headers depending on the call.