using Microsoft.AspNetCore.Http;

 private IHttpContextAccessor _accessor;

 public ApplyAppService(IHttpContextAccessor accessor)

        {

            _accessor = accessor;

        }

 string domain = Microsoft.AspNetCore.Http.Extensions.UriHelper.GetDisplayUrl(_accessor.HttpContext.Request);

 string host = _accessor.HttpContext.Request.Host.Value;

 string domain = _accessor.HttpContext.Connection.RemoteIpAddress;

备注：具体信息可以参考_accessor.HttpContext里的信息