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

string s = o as string; // 2

Is prefered, as it avoids the performance penalty of double casting.