Question

If there is a difference, what is the difference between the two ways of doing the following cast?

In this case e is a GridViewRowEventArgs object.

GridView gv = (GridView)e.Row.FindControl('gv'); //first way  GridView gv2 = e.Row.FindControl('gv') as GridView; //second way 

Answer 1

The differences are:

• If a cast fails, it throws an InvalidCastException.
• If the as operator fails, it just returns a null reference.
• You can’t use as with non-nullable value types (e.g. you can’t do ‘o as int‘).
• The cast operator is also used for unboxing. (as can be used to unbox to a nullable value type.)
• The cast operator can also perform user-defined conversions.

EDIT: I’ve written elsewhere about when I feel it’s appropriate to use which operator. That might be worth a read…