How bind IsSelected on ListView item?

I am new in c#. How can I bind something like "IsSelected" on xaml ListView to change selection specific items from code?

For example there is class Item with property IsGroupSelected that I want bind.

Also question: "How can I known that the myListViewCollection is finished render after add a lot of new items (so that the func myListViewCollection.ContainerFromItem(item) not return null)?"

MainPage.xaml

...
        <ListView 
            x:Name="myListViewCollection"
            VerticalAlignment="Top"
            Margin="0,20,0,0"
            SelectionMode="Multiple">

            <ListView.ItemTemplate>
                <DataTemplate>
                    <StackPanel HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                        <TextBlock Text="{Binding Path = Title}" FontWeight="Bold"/>
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

MainPage.xaml.cs

public class Item : INotifyPropertyChanged
    {
        private bool selectedGroup = false;

        public event PropertyChangedEventHandler PropertyChanged;
        public void NotifyPropertyChanged(String propertyName = "")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        public string Title { get; set; }
        public bool IsGroupSelected
        {
            get
            {
                return this.selectedGroup;
            }
            set
            {
                this.selectedGroup = value;
                NotifyPropertyChanged("IsGroupSelected");
            }
        }
        //public ObservableCollection<SubItem> SubItems { get; set; }

        public Item(string title, ObservableCollection<SubItem> subItems)
        {
            this.Title = title;
            //this.SubItems = subItems;
        }
    };

 public sealed partial class MainPage : Page
    {
        public ObservableCollection<Item> collectionItems = new ObservableCollection<Item>();


        public MainPage()
        {
            this.InitializeComponent();

            this.myListViewCollection.ItemsSource = this.collectionItems;

            this.Loaded += MainPage_Loaded;
        }

        private void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            collectionItems.Add(new Item("Title_1", null));
            collectionItems.Add(new Item("Title_2", null));
            collectionItems.Add(new Item("Title_3", null));

            collectionItems[1].IsGroupSelected = true;
        }
    }