WebApi POST method not found but GET works

Question

I tried many time today to call a web api function with POST (HttpClient.PostAsync) method . But unfortunately I can't. Only the call with GET (HttpClient.GetAsync) method working with success. I try to follow many sample on the net, but always the same error. ("Not Found")

Thank you so much if somebody can help me

Here is the C# Web API:

[RoutePrefix("NewAreaMap")]
public class NewAreaMapController: ApiController
{
    [HttpPost]
    [ActionName("PostCreateAreaTemp")]
    public AreaTemp PostCreateAreaTemp(double southLatitude, double westLongitude, double northLatitude, double eastLongitude, int countryId, int worldId)
    {
        AreaTemp newTempMap = new AreaTemp();
        //.....
        * * Here is the C# code from client side: * *
            using(var client = new HttpClient())
            {
                client.BaseAddress = new Uri(ConfigurationManager.AppSettings["SrvWebApiPath"].ToString());
                client.DefaultRequestHeaders.Accept.Clear();
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                var values = new Dictionary < string,
                    string > ()
                    {
                        {
                            "southLatitude", southLatitude.ToString()
                        },
                        {
                            "westLongitude", westLongitude.ToString()
                        },
                        {
                            "northLatitude", northLatitude.ToString()
                        },
                        {
                            "eastLongitude", eastLongitude.ToString()
                        },
                        {
                            "countryId", countryId.ToString()
                        },
                        {
                            "worldId", worldId.ToString()
                        }
                    };
                var content = new FormUrlEncodedContent(values);
                HttpResponseMessage response = await client.PostAsync("api/NewAreaMap/PostCreateAreaTemp", content)
                if (response.IsSuccessStatusCode)
                {
                    string jsonData = response.Content.ReadAsStringAsync().Result;
                    newAreTemp = JsonConvert.DeserializeObject < AreaTemp > (jsonData);
                }
        }

The GET call work well with the following Url :

HttpResponseMessage response = await client.GetAsync("api/NewAreaMap/GetAreaTemp/?latitudeAreaCenter=7.02&longitudeAreaCenter=9.05");

Answer 1

Since you're posting a JSON, you might as well send it as an object. Or if you still want to keep the dictionary and the signature for the method you could try:

var content = new StringContent(JsonConvert.SerializeObject(values),
            Encoding.UTF8, "application/json");

Instead of

var content = new FormUrlEncodedContent(values);

Here's an example with an object.

public class SampleObject
{
    public double SouthLatitude { get;  set; }
    public double WestLongitude { get; set; }
    public double NorthLatitude { get; set; }
    public double EastLongitude { get; set; }
    public int CountryId { get; set; }
    public int WorldId { get; set; }
}

And change your request.

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri(ConfigurationManager.AppSettings["SrvWebApiPath"].ToString());
    client.DefaultRequestHeaders.Accept.Clear();
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var obj = new SampleObject
    {
        SouthLatitude = southLatitude,
        WestLongitude = westLongitude,
        NorthLatitude = northLatitude,
        EastLongitude = eastLongitude,
        CountryId = countryId,
        WorldId = worldId
    };

    // Send it as StringContent.
    var request = new StringContent(JsonConvert.SerializeObject(obj),
        Encoding.UTF8, "application/json");

    HttpResponseMessage response = await client.PostAsync("api/NewAreaMap/PostCreateAreaTemp", request)
    if (response.IsSuccessStatusCode)
    {
        string jsonData = response.Content.ReadAsStringAsync().Result;
        newAreTemp = JsonConvert.DeserializeObject<AreaTemp>(jsonData);
    }
}

And the signature on the server.

public AreaTemp PostCreateAreaTemp(SampleObject sampleObject)

Or if needed:

public AreaTemp PostCreateAreaTemp([FromBody]SampleObject sampleObject)