WPF如果一个集合计数等于另一个集合计数，则隐藏TextBlock

<StackPanel>
    <TextBlock Text="集合1计数：" />
    <TextBlock Text="{Binding Collection1.Count}" />

    <TextBlock Text="集合2计数：" />
    <TextBlock Text="{Binding Collection2.Count}" />

    <TextBlock Text="结果：" />
    <TextBlock Text="隐藏TextBlock" Visibility="{Binding IsCountEqual, Converter={StaticResource BoolToVisibilityConverter}}" />
</StackPanel>

private bool isCountEqual;

public bool IsCountEqual
{
    get { return isCountEqual; }
    set
    {
        if (isCountEqual != value)
        {
            isCountEqual = value;
            OnPropertyChanged("IsCountEqual");
        }
    }
}

private void OnPropertyChanged(string propertyName)
{
    if (PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
}

private ObservableCollection<object> collection1;
private ObservableCollection<object> collection2;

public MainWindow()
{
    InitializeComponent();

    collection1 = new ObservableCollection<object>();
    collection2 = new ObservableCollection<object>();

    collection1.CollectionChanged += Collections_CollectionChanged;
    collection2.CollectionChanged += Collections_CollectionChanged;
}

private void Collections_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
    IsCountEqual = collection1.Count == collection2.Count;
}