C#后端调用WebApi地址

 using Newtonsoft.Json;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Text;
 using System.Threading.Tasks;

 namespace Services
 {
     public class HttpHelper<T> where T : class, new()
     {
         private Uri BaseUri
         {
             get
             {
                 return new Uri(GlobalString.BaseUrl);
             }
         }

         private Uri RequestUri(string requestUrl)
         {

             return new Uri(BaseUri, requestUrl);
         }

        //用Post还是用Get，要与WebApi的请求方式一致
         public async Task<T> GetPostResult(string requestUrl, FormUrlEncodedContent content)
         {
             using (var client = new HttpClient())
             {
                 client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(GlobalString.JsonHeader));
                 using (var response = await client.PostAsync(RequestUri(requestUrl), content))
                 {
                     if (response.IsSuccessStatusCode)
                     {
                         var productJsonString = await response.Content.ReadAsStringAsync();
                         return JsonConvert.DeserializeObject<T>(productJsonString);
                     }
                     return new T();
                 }
             }
         }
     }
 }

服务类

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;

 namespace Services
 {
     public class GlobalString
     {
         public static string JsonHeader
         {
             get
             {
                 return "application/json";
             }
         }

         public static string BaseUrl
         {
             get
             {
                 return "http://www.XXX.com";
             }
         }

         public static string GetApiUrl
         {
             get
             {
                 return "apiUrl";
             }
         }

     }
 }

全局常量类