PropertyChanged Null when not visible

hi,

I am having issue with a Collection shown in a Listview giving null on PropertyChanged when the item is not visible in the UI

Here is what i am trying to do.

I have a Checkbox in the list view that is registered to Checked

<ListView Name="lvSuites" 
                  Grid.Row="3" Grid.ColumnSpan="2"
                  Margin="10,10,10,10"
                  ItemsSource="{Binding Path=SuiteList, Mode=TwoWay}"
                  Background="{StaticResource PressedBrush}"
                  BorderBrush="{StaticResource SolidBorderBrush}" Foreground="Black"><ListView.View><GridView><GridViewColumn Width="Auto"><GridViewColumn.CellTemplate><DataTemplate><CheckBox IsChecked="{Binding Path=IsChecked, Mode=TwoWay}" Tag="{Binding Path=Name, Mode=TwoWay}" Checked="CheckBoxChecked" Unchecked="CheckBoxUnchecked"/></DataTemplate></GridViewColumn.CellTemplate></GridViewColumn><GridViewColumn Width="40" Header="#" ><GridViewColumn.CellTemplate><DataTemplate><TextBlock TextAlignment="Center" Text="{Binding Path=TestNumber, Mode=TwoWay}"/></DataTemplate></GridViewColumn.CellTemplate></GridViewColumn><GridViewColumn Width="300" Header="Suite"><GridViewColumn.CellTemplate><DataTemplate><TextBlock TextAlignment="Left" Text="{Binding Path=Name, Mode=TwoWay}"/></DataTemplate></GridViewColumn.CellTemplate></GridViewColumn></GridView></ListView.View></ListView>

When i call

private void ListSuiteAllMouseUp(object sender, MouseButtonEventArgs e)
        {
            foreach (var suite in ((ViewModel)DataContext).SuiteList)
            {
                suite.IsChecked = true;
            }
        }

PropertyChanged is null for the items that are not visible in the Scrollview of the Listview, but the ones that are visible call Checked of the checkbox

    public class Suite : INotifyPropertyChanged
    {
        private bool ischecked;
        private string name;
        private int testNumber;

        public Suite()
        {
            IsChecked = false;
        }

        public bool IsChecked
        {
            get { return ischecked; }
            set
            {
                ischecked = value;
                OnPropertyChanged("IsChecked");
            }
        }

        public int TestNumber
        {
            get { return testNumber; }
            set
            {
                testNumber = value;
                OnPropertyChanged("TestNumber");
            }
        }

        public string Name
        {
            get { return name; }
            set
            {
                name = value;
                OnPropertyChanged("Name");
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }

and i have my ViewModel 

DataContext = ViewModel();

private void CheckBoxChecked(object sender, RoutedEventArgs e)
        {
            //Do Something
        }

Can anyone help me get the PropertyChanged to not be null even for items that arnt visible in the ListView bc they are farther down the ScrollView becuase i want Checked to be called if i changed IsChecked property or if the user actually checks it. if i scroll down the list view and try setting IsChecked= true it works for the items that are now visible. It seems like PropertyChanged doesnt get attached till the object is rendered.