1 using (var httpClient = new HttpClient())
2            {               
3                //get
4                var url = new Uri("接口网络地址");
5                // response
6                var response = httpClient.GetAsync(url).Result;
7                var data = response.Content.ReadAsStringAsync().Result;
8               return data;//接口调用成功获取的数据
9            }

using (var httpClient = new HttpClient())
            {            
                //post
                var url = new Uri("接口网络地址");
                var body = new FormUrlEncodedContent(new Dictionary<string, string>
                {
                    { "参数1", "值1"},
                    { "参数2", "值2"},
                    { "参数3", "值3"},
                    { "参数4", "值4"},
                });
                // response
                var response = httpClient.PostAsync(url, body).Result; 
                var data = response.Content.ReadAsStringAsync().Result;
                return data;//接口调用成功数据
            }

httpClient.DefaultRequestHeaders.Add("Accept", "application/json");//设置请求头