C# ASP.NET MVC 配置允许跨域访问

web.config文件中的 system.webServer 节点下增加如下配置:

<system.web>
  <authentication mode="None" />
  <compilation debug="true" targetFramework="4.5" />
  <httpRuntime targetFramework="4.5" />
</system.web>
<system.webServer>
  <!--允许跨域 开始-->
  <httpProtocol>
    <customHeaders>
      <add name="Access-Control-Allow-Origin" value="*" />
      <add name="Access-Control-Allow-Headers" value="Content-Type" />
      <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE, OPTIONS" />
    </customHeaders>
  </httpProtocol>
  <!--允许跨域 结束-->
</system.webServer>

指定站点允许跨域访问(基础类)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace WebApplication1.App_Start
{
    public class AllowOriginAttribute
    {
        public static void onExcute(ControllerContext context, string[] AllowSites)
        {
            var origin = context.HttpContext.Request.Headers["Origin"];
            Action action = () =>
            {
                context.HttpContext.Response.AppendHeader("Access-Control-Allow-Origin", origin);

            };
            if (AllowSites != null && AllowSites.Any())
            {
                if (AllowSites.Contains(origin))
                {
                    action();
                }
            }
        }
    }

    public class ActionAllowOriginAttribute : ActionFilterAttribute
    {
        public string[] AllowSites { get; set; }
        public override void OnActionExecuting(System.Web.Mvc.ActionExecutingContext filterContext)
        {
            AllowOriginAttribute.onExcute(filterContext, AllowSites);
            base.OnActionExecuting(filterContext);
        }
    }
    public class ControllerAllowOriginAttribute : AuthorizeAttribute
    {
        public string[] AllowSites { get; set; }
        public override void OnAuthorization(System.Web.Mvc.AuthorizationContext filterContext)
        {
            AllowOriginAttribute.onExcute(filterContext, AllowSites);
        }

    }
}

指定Controller允许跨域访问

[ControllerAllowOrigin(AllowSites = new string[] { "http://localhost:52559" })]
public class CityController : Controller
{}

指定Action允许跨域访问

[HttpPost]
[ActionAllowOrigin(AllowSites = new string[] { "http://localhost:52559" })]
public ActionResult addCity(string userName, string password)
{
    var a = userName;
    var b = password;

    return Json(new
    {
        Code = 200,
        msg = "123",
        data = ""
    }, JsonRequestBehavior.AllowGet);
}

html页面

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>IndexTest</title>
    <script src="~/Scripts/jquery-1.8.0.js"></script>
    <script type="text/javascript">
        function login() {
            $.ajax({
                //几个参数需要注意一下
                type: "POST",//方法类型
                dataType: "json",//预期服务器返回的数据类型
                url: "http://localhost:5640/City/addCity",//url
                data: $('#form1').serialize(),
                success: function (result) {
                    console.log(result);//打印服务端返回的数据(调试用)
                    if (result.Code == 200) {
                        alert("SUCCESS");
                    }
                },
                error: function () {
                    alert("异常！");
                }
            });
        }
    </script>
</head>
<body>
    <form id="form1" οnsubmit="return false" action="##" method="post">
        <p>用户名：<input name="userName" type="text" id="txtUserName" tabindex="1" size="15" value="" /></p>
        <p>密　码：<input name="password" type="password" id="TextBox2" tabindex="2" size="16" value="" /></p>
        <p><input type="button" value="登录" οnclick="login()"><input type="reset" value="重置"></p>
    </form>
</body>
</html>

XMLHttpRequest（原生）

function loginNew() {

    var barcode = document.getElementById("Barcode").value;
    var name = document.getElementById("Name").value;

    console.log("1:" + barcode + ";2:" + name);

    //创建异步对象
    var xmlhttp = new XMLHttpRequest();
    //设置请求的类型及url
    xmlhttp.open('post', 'http://localhost:52556/api/AssetOa?IsAddAsset=true', true);

    //post请求一定要添加请求头才行不然会报错
    //xmlhttp.setRequestHeader("Content-type", "application/json");
    xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

    //发送请求
    xmlhttp.send('&Barcode=' + barcode + '&Name=' + name + '&AssetTypeId=1');
    xmlhttp.onreadystatechange = function () {
        // 这步为判断服务器是否正确响应
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
            console.log(xmlhttp.responseText);
        }
    };
}

D:\MyFile\测试项目\Solution1\WebApplication1