Direct casting vs 'as' operator?

Question

Consider the following code:

void Handler(object o, EventArgs e)
{
   // I swear o is a string
   string s = (string)o; // 1
   //-OR-
   string s = o as str         


        

Answer 1

All given answers are good, if i might add something: To directly use string's methods and properties (e.g. ToLower) you can't write:

(string)o.ToLower(); // won't compile

you can only write:

((string)o).ToLower();

but you could write instead:

(o as string).ToLower();

The as option is more readable (at least to my opinion).