ASP.NET return null or no connection from angular4 - asp.net

Question

I am trying to send JSON string from angular to asp.net server. I tried two things to get this data from client side.
1st : I have following code from both server and client side. I am sending a json string, and I expected to receive at backend for what I sent. However, I am just getting this server error before even getting the data.
POST "url" 404 (not found)
{"Message":"No HTTP resource was found that matches the request URI 'http://localhost:61476/api/testAPI/getData'.","MessageDetail":"No action was found on the controller 'getData' that matches the request."}
2nd : given that everything is same, i just added [FromBody] in my method like below. This doesn't return any server error and I am able to connect from my client side to server. However, I am getting my body message as null . I tried with Postman, but it seems that it works fine with Postman when I send same data.. I am aware that I can create some modelling in server code to match with my json string from client side, but I don't get why this doesn't work without modelling and also why connection fails without [FromBody].
All I need is to get JSON string from my client side. Can anyone please provide me advice on this?
public string getData([FromBody] string body)
angular
callServer(){
var json = {"name":"John Doe", "school": "A"};
let headers = new HttpHeaders();
headers.set('Content-Type', 'application/json');
this.appService.http.post('http://localhost:61476/api/testAPI/getData',
json,
{headers: headers})
.subscribe(data => {console.log(data), (err) => console.error("Failed! " + err);
})
}
server
namespace test.Controllers
{
public class testAPIController : ApiController
{
//
[HttpPost]
public string getData(string body)
{
try
{
Log.Info(string.Format("data {0}", body));
return "ok";
}
catch (Exception ex)
{
Log.Error(ex.Message);
return "error";
}
}
}}

Answer 1

Controller:
[HttpPost]
public string postData([FromBody]string body)
{
try
{
Log.Info(string.Format("data {0}", body));
return Json("ok");
}
catch (Exception ex)
{
Log.Error(ex.Message);
return "error";
}
}
Calling the server:
callServer() : Observable<string> {
var json = {"name":"John Doe", "school": "A"};
let headers = new Headers({ 'Content-Type': 'application/json' });
let options = new RequestOptions({ headers: headers });
let apiUrl = 'http://localhost:61476/api/testAPI/postData';
return this.appService.http.post(`${this.apiUrl}`, json, options)
.map((res: Response) => res.json())
.catch(this.handleErrorObservable);
}
private handleErrorObservable(error: Response | any) {
console.error(error.message || error);
return Observable.throw(error.message || error);
}
Calling the service:
this._service.callServer()
.subscribe(
res => { console.log(res) },
err => { console.log(err) }
)
console.log(res/err) will be your response from the POST call. Sorry if misinterpreted your question but your question is a little hard to follow.

Answer 2

404 error is "not found". You must decorate your API Class
[Route("api/TestApi/[action]")]
public class testAPIController : ApiController
{
[HttpPost]
[HttpPost, ActionName("getData")]
public string getData([FromBody]string body)
{}
}