C# Query WindowCollection [closed]

Question

I'm having elementary problem with trying to query System.Windows.WindowCollection at some point in my code i have

WindowCollection z =   Application.Current.Windows;

and would like to do z.Any();

Answer 1

The definition of WindowCollection Class is as follows

public sealed class WindowCollection : ICollection, IEnumerable

As you may see, it doesn't implement IEnumerable<Window>, so in order to have access to the most of the Enumerable extension methods, you need first to use Enumerable.Cast like this

z.Cast<Window>().Any();

Answer 2

LINQ works only with IEnumerable<T> interface. WindowCollection impliments only IEnumerable. There two options:

• Cast<T>() - this return IEnumerable but if collection has element which can't be casted to T exception will thrown.
• OfType<T>() - this returns IEnumerable. It skips element which can't be casted to T, that is why I prefer OfType.

Application.Current.Windows.OfType<Window>().Any();