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

First, the as keyword includes a is check.

if( o is A)
   a = (A) o;

is the same as

a = o as A;

Second, as does not convert the Type like a cast does, even if a conversion operator from Type A to B is defined.