Accepted answer

Just use:

ObservableCollection<Foo> x = new ObservableCollection<Foo>(enumerable);

That will do the required copying. There's no way of observing changes to the live query - although the idea of an ObservableQuery<T> is an interesting (though challenging) one.

If you want an extension method to do this, it's simple:

public static ObservableCollection<T> ToObservableCollection<T>
    (this IEnumerable<T> source)
    if (source == null)
        throw new ArgumentNullException("source");
    return new ObservableCollection<T>(source);


I wrote this library a few years ago.

It doesn't do exactly what you probably want, it does more. It's a Linq query provider which parses the expression tree, attaches to the referenced collections, and exposes another collection which emits events upon changes.

It's missing a few Linq operators. But the code base is not hard to extend.


IEnumerable is only the interface.

You would need to copy the content from the IEnumerable into the ObservableCollection. You can do this by passing your IEnumerable into the constructor of the ObersvableCollection when you create a new one


You need my ObservableComputations library maybe. That is .NET API for computations over INotifyPropertyChanged and INotifyColectionChanged (ObservableCollection) objects. Results of the computations are INotifyPropertyChanged and INotifyColectionChanged (ObservableCollection) objects.


You can use an ObservableCollection constructor for this:

ObservableCollection<MyClass> obsCol = 
        new ObservableCollection<MyClass>(myIEnumerable);


var linqResults = foos.Where(f => f.Name == "Widget");

var observable = new ObservableCollection<Foo>(linqResults);

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