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

What if the DependencyObject depObj was actually a FrameworkOtherTypeOfElement

Then depObj would not be null

but the attempted as Casts would both evaluate to null and _fe & _fce would both be null

as is equivalent to doing

if(I Can Cast This Object)
   //Then cast it
else
   //Return null