using System.Net.Http;

HttpClient client = new HttpClient();
/// POST ///

var values = new Dictionary<string, string>
{
    { "thing1", "hello" },
    { "thing2", "world" }
};

var content = new FormUrlEncodedContent(values);

var response = await client.PostAsync("http://www.example.com/recepticle.aspx", content);

var responseString = await response.Content.ReadAsStringAsync();

/// GET ///

var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");