The first answer to this question: What to do when the enum bitmask (flags) gets too large - this is exactly what I'm trying to do, only I don’t know how to save it to the database using LINQ to SQL and bind it to users without creating two tables for each thing / logical group.
This is best explained with code (this is LinqPad friendly, albeit incomplete):
// Requirements: // 1) Using LINQ to SQL // 2) Track User CRUD rights in different parts of an application (parts referred to below as 'Things') // For example: ThingA.Create, ThingB.Read, ThingB.Update, ThingC.Delete // Desired usage: if (User.IsAllowed(ThingA.Create)) { // allowed } else { // not allowed } // 3) Allow for more than 64 'Things' // 4) Do not want to refer to permissions using strings like User.IsAllowed("Create ThingA"); // // Scenario A: This works, but you would be limited to adding only 60 'Things' // Example usage: // User Bob = new User(); // var desiredPermissions = Permissions.Create | Permissions.ThingA; // Permission = Unique binary value combination of flags // if ((Bob.Permissions & desiredPermissions) == desiredPermissions) { // Bob has permission to Create ThingA [Flags] public enum Permissions : ulong { Create = 1 << 0, Read = 1 << 1, Update = 1 << 2, Delete = 1 << 3, // Limited to 60 'Things' ThingA = 1 << 4, ThingB = 1 << 5 } // User Model [Table(Name="Users")] public class User { [Column(IsPrimaryKey = true)] public string FName { get; set; } [Column] public Permissions Permissions { get; set; } public User() { } }
ScenarioB:
// // Scenario B: This would work too, but each new 'Thing' would need its own flag enum list stored in its own table (ThingXPermissions), // with another table linking ThingXPermissions.X to Users.ID (UserThingXPermissions) (yuck!) // Would like to avoid having to change database structure when adding more 'Things' in future. // User Model [Table(Name="Users")] public class User { [Column(IsPrimaryKey = true, IsDbGenerated = true)] public int ID { get; set; } private EntitySet<ThingAPermissions> userThingAPermissions = new EntitySet<ThingAPermissions>(); [Association(Name = "FK_User_UserThingAPermissions", Storage = "userThingAPermissions", OtherKey = "FK_User_Id", ThisKey = "ID")] public IEnumerable<ThingAPermissions> UserThingAPermissions { get { return userThingAPermissions; } } public IEnumerable<ThingAPermissions> ThingAPermissions { get { return (from up in UserThingAPermissions select up.UserThingAPermissions).AsEnumerable(); } } public User() { } } [Table(Name="UserThingAPermissions")] public class UserThingAPermissions { [Column(IsPrimaryKey = true)] public int FK_User_Id; private EntityRef<User> user; [Association(IsForeignKey = true, ThisKey = "FK_User_Id")] public User User { get { return user.Entity; } set { user.Entity = value; } } [Column] public ThingAPermissions ThingAPermissions { get; set; } } // ThingAPermissions [Flags] public enum ThingAPermissions : ulong { Create = 1 << 0, Read = 1 << 1, Update = 1 << 2, Delete = 1 << 3 }
Desired scenario:
// // Desired Scenario: Psuedo code of what I'd like to be able to do: // Single Permissions (CRUD) list // Single||simple Things list // Single||simple table associating UserX, ThingX, PermissionX // Example usage: // User Bob = new User(); // var desiredPermissions = Permissions.Create | Things.ThingZ; // Permission = Unique binary value combination of flags // if ((Bob.Permissions & desiredPermissions) == desiredPermissions) { // Bob has permission to Create ThingZ // Missing link: Combining enums and storing into database linked to user // eg // [Table = "UserPermissions"] // (User, Thing, Permission) // 1, ThingZ, Create // 1, ThingZ, Delete // 1, ThingX, Read // 2, ThingZ, Read // 2, ThingX, Delete [Flags] public enum Permissions : ulong { Create = 1 << 0, Read = 1 << 1, Update = 1 << 2, Delete = 1 << 3 } [Flags] public enum Things : ulong { ThingZ = 1 << 0, ThingY = 1 << 1, ThingX = 1 << 2, ThingW = 1 << 3 } [Table(Name="UserPermissions")] public class UserPermission { [Column(IsPrimaryKey = true)] public int FK_User_Id; private EntityRef<User> user; [Association(IsForeignKey = true, ThisKey = "FK_User_Id")] public User User { get { return user.Entity; } set { user.Entity = value; } } [Column] public int FK_Thing_Thing { get; set; } private EntityRef<Things> thing; [Association(IsForeignKey = true, ThisKey = "FK_User_Id")] public User User { get { return user.Entity; } set { user.Entity = value; } } [Column] public Permissions Permission { get; set; } }
Additional code attempts:
Allow WPF-based authorization using the Enum checkbox