.net HttpClient 发送 form-urlencoded 数据

using (var client = new HttpClient()){ ???var values = new List<KeyValuePair<string, string>>(); ???values.Add(new KeyValuePair<string, string>("thing1", "hello")); ???values.Add(new KeyValuePair<string, string>("thing2 ", "world")); ????var content = new FormUrlEncodedContent(values); ????var response = await client.PostAsync("http://www.mydomain.com/recepticle.aspx", content); ????var responseString = await response.Content.ReadAsStringAsync();}