Question

I a have 2 objects A and B. B is inherited from A and has some more properties.
I have IEnumerable{A} that contains only B objects.
What I want to do is:

list.Single(b => b.PropertyThatOnlyExistOnB == "something")

I would have expect something like this to work:

list.Single((B) b => b.PropertyThatOnlyExistOnB == "something")

But it doesn’t compile. For now I just doing:

B result = null;
foreach (b in list)
{
     if((B)b.PropertyThatOnlyExistOnB == "something")
     {
      result = (B)b;
     }
}

Is there a shorter way?
Thanks

Answer 1

Use the Enumerable.OfType<TResult> extension methods to filter/cast.

list.OfType<B>().Single(b => b.PropertyThatOnlyExistOnB == "something")