跨域访问被拒绝怎么办_request获取请求的域名

  HttpListenerRequest request = context.Request;
            context.Response.Headers.Add("Content-type", "text/html;charset=UTF-8");
            context.Response.ContentEncoding = Encoding.UTF8;

            context.Response.AppendHeader("Access-Control-Allow-Origin", "*");//后台跨域请求，通常设置为配置文件
            context.Response.AppendHeader("Access-Control-Allow-Credentials", "true"); //后台跨域请求
            context.Response.AppendHeader("Server", "MyIIS");//后台跨域请求，通常设置为配置文件

            context.Response.StatusCode = 200;//设置返回给客服端http状态代码 
            if (request.HttpMethod == "OPTIONS")
            {
                //后台跨域请求，必须配置
                context.Response.AppendHeader("Access-Control-Allow-Headers", "Authorization,Content-Type,Accept,Origin,User-Agent,DNT,Cache-Control,X-Mx-ReqToken,X-Requested-With");
                 context.Response.AppendHeader("Access-Control-Max-Age", "86400");
                
                SendMessage(context.Response, "OK");

                return;
            }else {
//其他正常请求。
.......
}