as Keyword C# with Example

 	using System;

	class BaseClass{}
	class DerivedClass : BaseClass{}
	
	class asKeywordUsing
	{
		public static void Main()
		{
			BaseClass baseObject = new BaseClass();
			DerivedClass derivedObject = new DerivedClass();
			
			if(baseObject is DerivedClass) 
				derivedObject = (DerivedClass) baseObject;
			else 
				derivedObject = null;
			
			if(derivedObject==null)
				Console.WriteLine("The cast in derivedObject=(DerivedClass)baseObject is NOT allowed.");
			else
				Console.WriteLine("The cast in derivedObject=(DerivedClass)baseObject is allowed");			
		}
	}