Rock.Model.GroupMemberService.GetByGroupId C# (CSharp) Method

        public IQueryable<GroupMember> GetByGroupId( int groupId, bool includeDeceased = false )
        {
            return Queryable("Person,GroupRole", includeDeceased)
                .Where( t => t.GroupId == groupId)
                .OrderBy( g => g.GroupRole.Order );
        }

        /// <summary>
        /// Executes the specified workflow.
        /// </summary>
        /// <param name="rockContext">The rock context.</param>
        /// <param name="action">The workflow action.</param>
        /// <param name="entity">The entity.</param>
        /// <param name="errorMessages">The error messages.</param>
        /// <returns></returns>
        /// <exception cref="System.NotImplementedException"></exception>
        public override bool Execute( RockContext rockContext, Model.WorkflowAction action, Object entity, out List<string> errorMessages )
        {
            var checkInState = GetCheckInState( entity, out errorMessages );
            if ( checkInState != null )
            {
                var family = checkInState.CheckIn.Families.Where( f => f.Selected ).FirstOrDefault();
                if ( family != null )
                {
                    var service = new GroupMemberService( rockContext );
                    foreach ( var groupMember in service.GetByGroupId( family.Group.Id ).AsNoTracking().ToList() )
                    {
                        if ( !family.People.Any( p => p.Person.Id == groupMember.PersonId ) )
                        {
                            var person = new CheckInPerson();
                            person.Person = groupMember.Person.Clone( false );
                            person.FamilyMember = true;
                            family.People.Add( person );
                        }
                    }

                    return true;
                }
                else
                {
                    errorMessages.Add( "There is not a family that is selected" );
                }

                return false;
            }

            return false;
        }