Virtual class Modifier

The Virtual modifier is used to specify that a method or property can be overridden in the derived child class. Unlike the other class modifiers which are used at the class level , the virtual modifier cannot be used at the class level, instead it is used to modify the behavior of the functions and properties of the class.

The following example defines a class with a virtual function which is overridden in the derived class.

    class VirtualBaseClass

    {

        public void NormalFunction()

        {

        }

        //

        public virtual void VirtualFunction()

        {

           

        }

    }

    //

    class VirtualChildClass : VirtualBaseClass

    {

        public override void NormalFunction()

        {

        }

        //

        public override void VirtualFunction()

        {

        }

    }

In the above example we are also trying to override the non-virtual function in the derived class but this will result in the following compiler error.

Error: VirtualChildClass.NormalFunction()': cannot override inherited member 'VirtualBaseClass.NormalFunction()'  because it is not marked virtual, abstract, or override