Filter Collection MVVM

Question

Hello,
I'm trying to figure out the best way to filter a collection in MVVM, using button Command. Here is the code. No errors are showing, so I know I'm missing something. I able to populate the listbox, but the filtering don't fire.

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using DK_Project.Model;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Collections.ObjectModel;
using System.Windows.Input;
using System.Windows.Data;
using System.Collections;
using System.ComponentModel;
namespace DK_Project.ViewModels
{
internal class EmployeeViewModel1:INotifyPropertyChanged
{


public EmployeeModel Employee { get; set; }
ObservableCollection<EmployeeModel> Employees = new ObservableCollection<EmployeeModel>();
public EmployeeViewModel1()
{
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Becky", LastName="Friedman", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/Becky.jpg", StDate="November 5, 2003", EmpId= 1011, Rating= 5, WorkGroup="Broiler Cook"});
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Bob", LastName="Broderick", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/Bob.jpg", StDate="November 4, 2003", EmpId= 1012, Rating= 5, WorkGroup="Broiler Cook"});
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Eric", LastName="Clapton", ContactTitle="Manager", EmpImage="/Resources/EmployeImages/Bubba.jpg", StDate="November4, 2003", EmpId= 1013, Rating= 5, WorkGroup="Saute Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Jesus", LastName="Weinman", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/Jesus.jpg", StDate="November 9, 2003", EmpId= 1014, Rating= 5, WorkGroup="Saute Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Steve", LastName="Vai", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/FOH1.jpg", StDate="November 9, 2003", EmpId= 1015, Rating= 5, WorkGroup="Manager" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Jeff", LastName="Bonamassa", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/SousChef1.jpg", StDate="November 5, 2003", EmpId= 1016, Rating= 5, WorkGroup="Manager" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Chef ", LastName="Gates", ContactTitle="Chef", EmpImage="/Resources/EmployeImages/Chef1.jpg", StDate="November 5, 2003", EmpId= 1017, Rating= 5, WorkGroup="Manager"});
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Mike", LastName="Anastasio", ContactTitle="SousChef", EmpImage="/Resources/EmployeImages/Mike.jpg", StDate="November 5, 2003", EmpId= 1018, Rating= 5, WorkGroup="Saute Cook"});
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Markus", LastName="Lommis", ContactTitle="SousChef", EmpImage="/Resources/EmployeImages/Markus.jpg", StDate="November 5, 2003", EmpId= 1019, Rating= 5, WorkGroup="Pantry Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Bubba", LastName="Paisly", ContactTitle="AM Supervisor", EmpImage="/Resources/EmployeImages/Bubba.jpg", StDate="November 5, 2003", EmpId= 1020, Rating= 5, WorkGroup="Pantry Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Sara", LastName="Gilbert", ContactTitle="PM Supervisor", EmpImage="/Resources/EmployeImages/Sara.jpg", StDate="November 5, 2003", EmpId= 1021, Rating= 5, WorkGroup=" Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Samuel", LastName="Vaughn", ContactTitle="PrepCook", EmpImage="/Resources/EmployeImages/Samuel.jpg", StDate="November 5, 2003", EmpId= 1031, Rating= 5, WorkGroup="Broiler Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Sara", LastName="Malmsteen", ContactTitle="PrepCook", EmpImage="/Resources/EmployeImages/sara.jpg", StDate="November 5, 2003", EmpId= 1041, Rating= 5, WorkGroup="Broiler Cook"});
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Zakk", LastName="Satriani", ContactTitle="PrepCook", EmpImage="/Resources/EmployeImages/SousChef2.jpg", StDate="November 5, 2003", EmpId= 1051, Rating= 5, WorkGroup="Manager"});
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Clara", LastName="Rhoads", ContactTitle="PrepCook", EmpImage="/Resources/EmployeImages/Clara.jpg", StDate="November 5, 2003", EmpId= 1061, Rating= 5, WorkGroup="Fry Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Susie", LastName="Meola", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/Susie.jpg", StDate="November 5, 2003", EmpId= 1071, Rating= 5, WorkGroup="Fry Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Ted", LastName="Hendrix", ContactTitle="LineCook", EmpImage="/Resources/EmployeImages/Ted.jpg", StDate="November 5, 2003", EmpId= 1081, Rating= 5, WorkGroup="Prep Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Ron", LastName="Lee", ContactTitle="DishWasher", EmpImage="/Resources/EmployeImages/Ron.jpg", StDate="November 5, 2003", EmpId= 1091, Rating= 5, WorkGroup="Prep Cook" });
Employees.Add(new EmployeeModel() { CompanyName="Digital Kitchen", Location="Eden Prairie", FirstName="Linda", LastName="Johnson", ContactTitle="DishWasher", EmpImage="/Resources/EmployeImages/Linda.jpg", StDate="November 5, 2003", EmpId= 1101, Rating= 5, WorkGroup="Prep Cook" });
}
public ObservableCollection<EmployeeModel> EmployeeList
{
get { return Employees; }

}
private MyCommand _filterCommand;
public MyCommand FilterCommand
{
get { return _filterCommand; }
set
{
_filterCommand = value;
OnPropertyChanged("FilterCommand");
}
}



private void InitializeCommands()
{
FilterCommand = new MyCommand(FilterWorkGroup);
}
private void FilterWorkGroup()
{
this.GetListCollectionView().Filter = this.FilterWG;
}
private bool FilterWG(object obj)
{
if (obj as EmployeeModel != null
&& (obj as EmployeeModel).WorkGroup == "Broiler Cook")
{ return true; } return false;
}

private ListCollectionView GetListCollectionView()
{
return (ListCollectionView)CollectionViewSource.GetDefaultView(this.EmployeeList);
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
public class MyCommand : ICommand
{
Action _action;
public MyCommand(Action action)
{
_action = action;
}
#region ICommand Members
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
_action.Invoke();
}
#endregion
}
}

 
 
and in the xaml:
 

 

             <ListBox  Height="98" ItemsSource="{Binding}" ItemTemplate="{StaticResource Test}"  HorizontalAlignment="Left" Margin="440,17,0,0" Name="listBox1" VerticalAlignment="Top" Width="228" />
            <Button Content="Button" HorizontalAlignment="Right" Height="24" Margin="0,16,274,0" VerticalAlignment="Top" Width="80" Command="{Binding FilterWorkGroup}"/>

 
 
Reagrds,
Rick