-I have a ListView, and its SelectedItem property is bound to EmployeeModel SelectedEmployee in my VM, and it implements the Set method from MVVM Light. (Basically, OnPropertyChanged, but the MVVM Light version.)

-I have three more ListViews (more, but for simplicity's sake, we'll say three.) They are bound to the following properties in my VM: ObservableCollection<EquipmentAssignmentModel>EquipmentAssignments_StandardIssue, ObservableCollection<EquipmentAssignmentModel>EquipmentAssignments_AdHoc, and <VehicleAssignmentModel>VehicleAssignments.

-EmployeeModel has as these properties: ObservableCollection<EquipmentAssignmentModel>EquipmentAssignments and ObservableCollection<VehicleAssignmentModel>VehicleAssignments.

-When I select a new person in my Employee ListView, SelectedEmployee in my VM is updated. I also want to update the other collections, so that the ListViews display the respective collections. I achieved this by setting the EquipmentAssignment_AdHoc, EquipmentAssignment_StandardIssue, and VehicleAssignment properties in the setter of the SelectedEmployee property. It looks like this:

        private EmployeeModel _selectedEmployee;
        public EmployeeModel SelectedEmployee
        {
            get { return _selectedEmployee; }
            set
            {
                if (Set(ref _selectedEmployee, value))
                {
                    Messenger.Default.Send(new EmployeeToken(value));
                    if (EquipmentAssignments_StandardIssue != null)
                    {
                        EquipmentAssignments_StandardIssue.Clear();
                    }
                    if (EquipmentAssignments_AdHoc != null)
                    {
                        EquipmentAssignments_AdHoc.Clear();
                    }
                    if (SelectedEmployee.EquipmentAssignments != null)
                    {
                        var resultFalse = SelectedEmployee.EquipmentAssignments.Where(x => x.IsStandardIssue == false);
                        var resultTrue = SelectedEmployee.EquipmentAssignments.Where(x => x.IsStandardIssue == true);
                        if (resultFalse != null )
                        {
                            foreach(EquipmentAssignmentRecordModel record in resultFalse)
                            {
                                EquipmentAssignments_AdHoc.Add(record);
                            }
                        }
                        if (resultTrue !=null)
                           foreach (EquipmentAssignmentRecordModel record in resultTrue)
                            {
                                EquipmentAssignments_StandardIssue.Add(record);
                            }
                    }
                }
            }
        }

        public ObservableCollection<VehicleAssignmentRecordModel> VehicleAssignments { get; set; }
        public ObservableCollection<EquipmentAssignmentRecordModel> EquipmentAssignments_StandardIssue { get; private set; }
        public ObservableCollection<EquipmentAssignmentRecordModel> EquipmentAssignments_AdHoc { get; private set; }

And it works great. Still, since I haven't seen this technique used anywhere else, I'm guessing there is a "right" way to do it that I've not been able to find through Googling.

My first attempt was to use the setters of the three properties to set their own values, so for instance:

private ObservableCollection<EquipmentAssignmentRecordModel>_equipmentAssignments_StandardIssue; 
public ObservableCollection<EquipmentAssignmentRecordModel> EquipmentAssignments_StandardIssue
        {
            get { return _equipmentAssignments_StandardIssue); }
            set { _equipmentAssignments_StandardIssue == SelectedEmployee.EquipmentAssignments.Where(x => x.IsStandardIssue == true); }
        }

This did not work because even though the SelectedEmployee changed (and indeed it did change in the EquipmentAssignments_StandardIssue setter when I stepped through the code), it didn't notify the ObservableCollections of the change.

So, should I rewrite this code to follow some best practice?