Type casting means conversion of one type into another type. For Ex: public partial class InheritanceEx3 : System.Web.UI.Page {protected void Page_Load(object sender, EventArgs e){B b = new B();A A = b; Casting operation for getting parent class object Down castingB b1 = (B)A; Casting operation for getting Child class object UPcasting} } public class A {public int _x;public A(int X){_x = X;} } public class B : A { }For learning more about C# interview question you can refer this link c# interview questions