public async Task <IActionResult> AddCustomerCollection([FromBody] IEnumerable <CustomerForCreationDto> modelCollection) { var customers = _mapper.Map <IReadOnlyList <Customer> >(modelCollection); var customersAdded = _mapper.Map <IReadOnlyList <CustomerDto> >(await _customerService.AddRangeAsync(customers)); var idsAsString = string.Join(",", customersAdded.Select(c => c.CustomerID)); //return Ok(customersAdded); return(CreatedAtRoute("GetCustomerCollection", new { ids = idsAsString }, customersAdded)); }