using System.ComponentModel.DataAnnotations; namespace Landmark.OLA.Models { public class OlaModel { //This will either hold an ToString'ed int or a 36-char long GUID [StringLength(36)] public string Id { get; set; } public Guid GetOrCreateGuid() { if (Guid.TryParse(Id, out Guid parsedGuid)) { return parsedGuid; } else { var newGuid = Guid.NewGuid(); Id = newGuid.ToString(); return newGuid; } } } }