How to display collection property on PropertyGrid?

Hello,

I want to display collection property on PropertyGrid.

I understand that I should use TypeDescriptorFactory, but I'm not sure how to display collection property.

Would you please tell me how to do it?

<grids:PropertyGrid DataObject="{Binding Properties}" />

DataContext is :

public class MainWindowViewModel
{
  public List<PropertyItem> Properties { get; } = new List<PropertyItem>();

  public MainWindowViewModel()
  {
    Properties.Add(new PropertyItem(){Name = "CustomerName", Value = "AAAA"});
    Properties.Add(new PropertyItem(){Name = "Country", Value = "US"});

    var phoneNumbersProperty = new PropertyItem(){Name = "Phone numbers"};
    phoneNumbersProperty.Children.Add(new PropertyItem(){Name = "Fax", Value = "491-294-1356"});
    phoneNumbersProperty.Children.Add(new PropertyItem(){Name = "Voice", Value = "491-198-1285"});
    Properties.Add(phoneNumbersProperty);
  }

  public class PropertyItem
  {
    // PropertyName
    public string Name { get; set; }

    // PropertyValue
    public object Value { get; set; }

    // Children properties (Expandable items)
    public List<PropertyItem> Children { get; } = new List<PropertyItem>();
  }
}

I want to display it in the same way as lower PropertyGrid of "Custom Data Factory" sample.