public void ConfigureServices(IServiceCollection services)

        {

            services.AddCors(options =>

            {

                options.AddPolicy("any", builder =>

                {

                    //builder.AllowAnyOrigin() //允许任何来源的主机访问

                    builder

                    .WithOrigins("http://*.*.*.*")//.SetIsOriginAllowedToAllowWildcardSubdomains()//设置允许访问的域

                    .AllowAnyMethod()

                    .AllowAnyHeader()

                    .AllowCredentials();//

                });

            });

            services.AddControllers();

        }

public class CorsMiddleware

    {

        private readonly RequestDelegate _next;

        public CorsMiddleware(RequestDelegate next)

        {

            _next = next;

        }

        public async Task Invoke(HttpContext context)

        {

            if (!context.Response.Headers.ContainsKey("Access-Control-Allow-Origin"))

            {

                context.Response.Headers.Add("Access-Control-Allow-Origin", "*");

            }

            await _next(context);

        }

    }

 app.UseMiddleware<CorsMiddleware>();