Cast LINQ result to ObservableCollection

Question

The fact that it is a LINQ result might perhaps not be relevant for the question, but I'm mentioning it anyway - since this is the context which has resulted in this question.

I run a LINQ query. The result is an;

IEnumerable<MyClass> 

I want to put the result into an ObservableCollection;

ObservableCollection<MyClass> 

How do I do this cast? (without running through the IEnumerable and copying elements to the ObservableCollection). I notice LINQ has got a few To..() functions, but it doesn't seem to help me for this cast..?

Answer 1

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);
}

Answer 2

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

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

Answer 3

You can use an ObservableCollection constructor for this:

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