RemoveAll for ObservableCollections?

Question

I am looking for Linq way (like RemoveAll method for List) which can remove selected items from my ObservableCollection.

I am too new to create an extension method f

Answer 1

This is my version of an extension method solution, which is only a slight variation on the accepted answer, but has the advantage that the count returned is based on confirmed removal of the item from the collection:

public static class ObservableCollectionExtensionMethods
{
    /// 

    /// Extends ObservableCollection adding a RemoveAll method to remove elements based on a boolean condition function
    /// 
    /// The type contained by the collection
    /// The ObservableCollection
    /// A function that evaluates to true for elements that should be removed
    /// The number of elements removed
    public static int RemoveAll(this ObservableCollection observableCollection, Func condition)
    {
        // Find all elements satisfying the condition, i.e. that will be removed
        var toRemove = observableCollection
            .Where(condition)
            .ToList();

        // Remove the elements from the original collection, using the Count method to iterate through the list, 
        // incrementing the count whenever there's a successful removal
        return toRemove.Count(observableCollection.Remove);
    }
}