办公室加载项：访问apicontroller时获取404

Question

我正在学习根据官方教程。我遵循 插入图像节，但发现加载项无法正常工作。当我单击“插入映像”按钮时，访问的加载项/api/photo/通过ajax，但状态代码始终为404。

这是我单击按钮时调用的函数：

function insertImage() {
    // Get image from from web service (as a Base64 encoded string).
    $.ajax({
        url: "/api/Photo/", success: function (result) {
            insertImageFromBase64String(result);
        }, error: function (xhr, status, error) { // always 404
            showNotification("Error", "Oops, something went wrong.");
        }
    });
}

这​​是ApiconTroller：

namespace HelloWorldWeb.Controllers
{
    public class PhotoController : ApiController
    {
        public string Get()
        {
            string url = "http://www.bing.com/HPImageArchive.aspx?format=xml&idx=0&n=1";

            // Create the request.
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            WebResponse response = request.GetResponse();

            using (Stream responseStream = response.GetResponseStream())
            {
                // Process the result.
                StreamReader reader = new StreamReader(responseStream, Encoding.UTF8);
                string result = reader.ReadToEnd();

                // Parse the xml response and to get the URL.
                XmlDocument doc = new XmlDocument();
                doc.LoadXml(result);
                string photoURL = "http://bing.com" + doc.SelectSingleNode("/images/image/url").InnerText;

                // Fetch the photo and return it as a Base64 encoded string.
                return getPhotoFromURL(photoURL);
            }
        }

        private string getPhotoFromURL(string imageURL)
        {
            var webClient = new WebClient();
            byte[] imageBytes = webClient.DownloadData(imageURL);
            return Convert.ToBase64String(imageBytes);
        }
    }
}

我想知道如何配置路由器。尚未在教程中讨论它，我很困惑它是否是自动配置的。

谢谢你！