Classic Eager loading for entity framework.

notes.cs

        // GET api/values
        [HttpGet, Route("branches")]
        public IActionResult Branches()
        {
            //_context.Regions.Where(u=>u.Business.BusinessId == )

            var regions = _context.Regions
                .Include(x => x.Branches)
                .Include(x => x.Business)
                .ToList();

            foreach (var business in _context.Businesses)
            {
                foreach (var region in regions.Where(u => u.BusinessFkId == business.BusinessId))
                {
                    Debug.WriteLine(region.Name);
                }

                //foreach (var iRegion in business.Regions)
                //{
                //    Debug.WriteLine(iRegion.Name);
                //}
            }

            return new ObjectResult(regions);

            //return new ObjectResult(JsonConvert.SerializeObject(_context.Branches));
        }