Use 'is' to avoid an invalid cast. : is « Operator « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Operator
3. is

using System; 
 
class A {} 
class B : A {} 
 
class CheckCast { 
  public static void Main() { 
    A a = new A(); 
    B b = new B(); 
 
    if(a is B)
      b = (B) a; 
  } 
}