Is there more to the C# “as” keyword than simple casting?

Question

I\'m working through Josh Smith\'s CommandSink code obviously do not understand something about the \"as\" keyword in C#.

I don\'t understand why he wrote the line:

Answer 1

as does "cast, if it is", and equivalent to:

(X is TYPE) ? (TYPE) X : null

it is however, more efficient than is + cast.

depObj may implement either interface, none, or both.