Adding a range of values to an ObservableCollection efficiently

Question

I have an ObservableCollection of items that is bound to a list control in my view.

I have a situation where I need to add a chunk of values to the star

Answer 1

To make the above answer useful w/o deriving a new base class using reflection, here's an example:

public static void InsertRange(this ObservableCollection collection, IEnumerable items)
{
  var enumerable = items as List ?? items.ToList();
  if (collection == null || items == null || !enumerable.Any())
  {
    return;
  }

  Type type = collection.GetType();

  type.InvokeMember("CheckReentrancy", BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.NonPublic, null, collection, null);
  var itemsProp = type.BaseType.GetProperty("Items", BindingFlags.NonPublic | BindingFlags.FlattenHierarchy | BindingFlags.Instance);
  var privateItems = itemsProp.GetValue(collection) as IList;
  foreach (var item in enumerable)
  {
    privateItems.Add(item);
  }

  type.InvokeMember("OnPropertyChanged", BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.NonPublic, null,
    collection, new object[] { new PropertyChangedEventArgs("Count") });

  type.InvokeMember("OnPropertyChanged", BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.NonPublic, null,
    collection, new object[] { new PropertyChangedEventArgs("Item[]") });

  type.InvokeMember("OnCollectionChanged", BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.NonPublic, null, 
    collection, new object[]{ new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset)});
}