没有& # 39;Access-Control-Allow-Origin& # 39;标头显示在web api中请求的资

我正在制作一个从angularJs到web api的post请求。但每次我得到这个错误

XMLHttpRequest cannot load http://localhost:45525/api/account/register. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:45725' is therefore not allowed access. The response had HTTP status code 500.

我遵循教程

为了解决这个问题，我还安装了

Install-Package Microsoft.AspNet.WebApi.Cors

然后我加上

config.EnableCors();

inside WebApiConfig Register Method.

我还添加了

    [RoutePrefix("api/Account")]
    public class AccountController : ApiController
    {
        private AuthRepository _repo = null;
        public AccountController()
        {
            _repo = new AuthRepository();
        }
        // POST api/Account/Register
        [EnableCors("*", "*", "PUT, POST")]
        [AllowAnonymous]
        [Route("Register")]
        [HttpPost]
        public async Task<IHttpActionResult> Register(UserModel userModel)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            IdentityResult result = await _repo.RegisterUser(userModel);
            return Ok();
        }
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                _repo.Dispose();
            }
            base.Dispose(disposing);
        }
}

at account controller。但是我还是遇到了同样的问题。

AngularCode

var _saveRegistration = function (registration) {
  var serviceBase = 'http://localhost:45525/';
  _logOut();
  return $http.post(serviceBase + 'api/account/register', registration)
     .then(function (response) {
            return response;
     }); 
};

[EnableCors("*", "*", "PUT,POST")]