Add elements from IList to ObservableCollection

Question

I have an ObservableCollection, and I\'d like to set the content of an IList to this one. Now I could just create a new instance of the collection..:

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Answer 1

You could do

public void Foo(IList<Bar> list)
{
    list.ToList().ForEach(obs.Add);
}

or as an extension method,

    public static void AddRange<T>(this ObservableCollection<T> collection, IEnumerable<T> items)
    {
        items.ToList().ForEach(collection.Add);
    }    

Answer 2

Here is an descendant to ObservableCollection<T> to add a message efficient AddRange, plus unit tests:

ObservableCollection Doesn't support AddRange method, so I get notified for each item added, besides what about INotifyCollectionChanging?

Answer 3

If you do want to instantiate an observable collection and want to add a new range into Observable collection you can follow the following method I have tried:

var list = new List<Utilities.T>();
            list.AddRange(order.ItemTransactions.ToShortTrans());
            list.AddRange(order.DealTransactions.ToShortTrans());
            ShortTransactions = new ObservableCollection<T>(list);

in this way you can add the range into ObservableCollection without looping.

Answer 4

Looping is the only way, since there is no AddRange equivalent for ObservableCollection.

Answer 5

You could write your own extension method if you are using C#3+ to help you with that. This code has had some basic testing to ensure that it works:

public static void AddRange<T>(this ObservableCollection<T> coll, IEnumerable<T> items)
{
    foreach (var item in items)
    {
        coll.Add(item);
    }
}

Answer 6

There is a library that solves this problem. It contains an ObservableList that can wrap a List. It can be used in the following way:

List<Bar> currentList = getMyList();
var obvList = new ObservableList<Bar>(currentList);

https://github.com/gsonnenf/Gstc.Collections.ObservableLists