Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:9001/api/size/get. (Reason: CORS header 'Access-Control-Allow-Origin' missing).

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:9001/api/size/get. (Reason: CORS header ‘Access-Control-Allow-Origin‘ missing).

打开API项目录，命名用NuGet安装Microsoft.AspNet.WebApi.Cors:

 在WebApiConfig.cs中，添加下面代码：

 private static void EnableCrossSiteRequests(HttpConfiguration config)
        {
            var cors = new EnableCorsAttribute(
              origins: "*",
              headers: "*",
              methods: "*"
              );
            config.EnableCors(cors);
        }

Source Code

在路由中启用CROSS，说对整个API项目有效...

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:9001/api/size/get. (Reason: CORS header 'Access-Control-Allow-Origin' missing).

原文：http://www.cnblogs.com/insus/p/5666333.html