httpclient后台和ajax请求跨域

1、httpclient

$("#btnGet").on("click", function () {
                $.post("WebService.asmx/GetWebService", function (d) {
                    $("#getContent").html(d);
                });
            });

<input type="button" id="btnGet" value="按钮client"/>

<div id="getContent"></div>

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Web;
using System.Web.Services;

/// <summary>
/// WebService 的摘要说明
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
// 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消注释以下行。 
// [System.Web.Script.Services.ScriptService]
public class WebService : System.Web.Services.WebService {

    public static readonly string url = ConfigurationManager.AppSettings["url_get"].ToString();
    public WebService () {

        //如果使用设计的组件，请取消注释以下行 
        //InitializeComponent(); 
    }

    [WebMethod]
    public string HelloWorld() {
        return "Hello World";
    }
    [WebMethod]
    public void GetWebService()
    {
        string result = "";
        using (HttpClient client = new HttpClient())
        {
            client.BaseAddress = new Uri(url);
            try
            {
                using (Stream stream = client.GetStreamAsync(url).Result)
                {
                    using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
                    {
                        result = reader.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        Context.Response.Write(result);
        Context.Response.End();
    }
}

<appSettings>
    <add key="url_get" value="http://10.100.22.54:8095/api/BookChapters"/>
  </appSettings>

webpai

using System.Collections;
using System.Collections.Generic;
using System.Web.Http;
using WebApplication1.Models;
using System.Linq;
using Newtonsoft.Json;
using WebApplication1.App_Start;

namespace WebApplication1.Controllers
{
    [AllowCrossSiteJson]
    public class BookChaptersController:ApiController
    {
        // GET api/bookchapters
        [HttpGet]
        public IEnumerable<BookChapter> Get()
        {
            return chapters;
        }

        // GET api/bookchapters/5
        public BookChapter Get(int id)
        {
            return chapters.Where(c => c.Number == id).SingleOrDefault();
        }

        // POST api/bookchapters
        [AcceptVerbs("POST")]
        [ActionName("bookchapter")]
        public void PostBookChapter([FromBody]BookChapter value)
        {
            chapters.Add(value);
        }

        // PUT api/bookchapters/5
        public void PutBookChapter(int id, [FromBody]BookChapter value)
        {
            chapters.Remove(chapters.Where(c => c.Number == id).Single());
            chapters.Add(value);
        }

        // DELETE api/bookchapters/5
        public void DeleteBookChapter(int id)
        {
            chapters.Remove(chapters.Where(c => c.Number == id).Single());
        }

        private static List<BookChapter> chapters;

        static BookChaptersController()
        {
            chapters = new List<BookChapter>()
            {
                new BookChapter{Number=1,Title=".Net Architecture",Pages=20},
                new BookChapter{Number=2,Title=".Net ",Pages=120},
                new BookChapter{Number=3,Title=".Net a",Pages=480},
                new BookChapter{Number=4,Title=".Net b",Pages=200},
                new BookChapter{Number=5,Title=".Net c",Pages=210},
                new BookChapter{Number=17,Title=".Net d",Pages=230},
                new BookChapter{Number=42,Title=".Net e",Pages=270},
                new BookChapter{Number=43,Title=".Net f",Pages=320},
                new BookChapter{Number=50,Title=".Net g",Pages=520}
            };
        }
    }
}

2、ajax

$("#btnGetClient").on("click", function () {
                $.get("http://10.100.22.54:8095/api/BookChapters", function (d) {
                    $("#getContent").html(JSON.stringify(d));
                });
            })

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http.Filters;

namespace WebApplication1.App_Start
{
    public class AllowCrossSiteJsonAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
        {
            if (actionExecutedContext.Response != null) { actionExecutedContext.Response.Headers.Add("Access-Control-Allow-Origin", "*"); }
            base.OnActionExecuted(actionExecutedContext);
        }
    }
}