Empty respond when Post data in C#

Question

when I post username and password and IP address I got only an empty response. my C# code is:

public async void APILogin(string user, string pass, string ip)
{
    var person = new Userinfo { username = user, password = pass, ip = ip };
    var json = JsonConvert.SerializeObject(person);
    var data = new StringContent(json, Encoding.UTF8, "application/x-www-form-urlencoded");
    var url = new Uri("http://localhost/login/dblogin.php") ;

    HttpClient client = new HttpClient();

    HttpResponseMessage response = await client.PostAsync(url,content:data);
    HttpContent content = response.Content;
    string myContent = await content.ReadAsStringAsync();
    MessageBox.Show(myContent, "Info");
}
public class Userinfo 
{
    public String username { get; set; }
    public String password { get; set; }
    public String ip { get; set; }
}

Answer 1

I used this and it is worked.

var url = "http://localhost/login/dblogin.php";
            HttpClient client = new HttpClient();
            StringContent data = new StringContent("username="+user+"&password="+pass+"&ip="+ip);
            data.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/x-www-form-urlencoded");
            HttpResponseMessage response = await client.PostAsync(url, data);
            response.EnsureSuccessStatusCode();
            HttpContent content = response.Content;
            string myContent = await content.ReadAsStringAsync();
            loginResp apiResponse = JsonConvert.DeserializeObject<loginResp>(myContent);