public async Task <IActionResult> AddCustomer([FromBody] CustomerDTO dto) { if (dto == null || string.IsNullOrWhiteSpace(dto.FirstName) || string.IsNullOrWhiteSpace(dto.LastName) || string.IsNullOrWhiteSpace(dto.BirthDate)) { var errorMessage = dto.CreateErrorMessage(); return(BadRequest(errorMessage)); } if (!DateTime.TryParse(dto.BirthDate, out var dt)) { return(BadRequest("invalid birth date")); } await Model.AddCustomerAsync(dto); return(StatusCode(201)); }