CORS无法使用Angular 5

Question

我有ASP。NET核心API及其在Angular 5中的应用。我在启动中添加了代码。cs启用cors并允许所有来源，但它仍然给了我一个错误

请求的资源上不存在“Access Control Allow Origin”标头。起源'http://localhost:4200因此，不允许访问。响应的HTTP状态代码为500。

下面是我的web api代码：

  public void ConfigureServices(IServiceCollection services)
    {
        WriteToFile("In configure service");
        try
        {
            // Enable Cors
            services.AddCors();
            services.AddMvc();
        }
        catch
        {
            WriteToFile("Not Connected in StartUP");
        }
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        try
        {
            app.UseCors(builder =>
               builder.AllowAnyOrigin()
               .AllowAnyHeader()
               .AllowAnyMethod());

            app.UseMvc();

            WriteToFile("After cors use In configure");

        }
        catch(Exception ex)
        {
            WriteToFile("Error in  configure"+ex.Message);
        }
    }

Answer 1

嘿，我想你应该把

[EnableCors(origins: "**http:/...(Here the website you want to enter)**", headers: "*", methods: "*")] 

在控制器中的类之前。