void LoadOpleidingen(SqliteConnection conn)
        {
            bool shouldClose = false;

            // Is the database already open?
            if (conn.State != ConnectionState.Open)
            {
                shouldClose = true;
                conn.Open();
            }

            // Execute query
            using (var command = conn.CreateCommand())
            {
                try
                {
                    // Create new command
                    command.CommandText = "SELECT DISTINCT ID FROM [Opleiding]";

                    using (var reader = command.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            var opleiding = new OpleidingModel();
                            var id        = (string)reader["ID"];

                            opleiding.Load(conn, id);

                            //AddPersoon(persoon);
                            Opleidingen.Add(opleiding);
                        }
                    }
                }
                catch (Exception Exception)
                {
                    Debug.WriteLine(Exception.Message);
                }
            }

            if (shouldClose)
            {
                conn.Close();
            }
        }
        public bool AddOpleiding(OpleidingModel _opleiding)
        {
            Opleidingen.Add(_opleiding);

            return(true);
        }