/* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852 */ // Use is to avoid an invalid cast. using System; class A {} class B : A {} public class CheckCast { public static void Main() { A a = new A(); B b = new B(); // Check to see if a can be cast to B. if(a is B) // if so, do the cast b = (B) a; else // if not, skip the cast b = null; if(b==null) Console.WriteLine("Cast b = (B) a is NOT allowed."); else Console.WriteLine("Cast b = (B) a is allowed"); } }