Virtual functions implement the concept of polymorphism are the same as in C#, except that you use the override keyword with the virtual function implementaion in the child class. The parent class uses the same virtual keyword. Every class that overrides the virtual method will use the override keyword.
class Shape { publicvirtualvoid Draw() { Console.WriteLine("Shape.Draw") ; } }
Virtual functions implement the concept of polymorphism are the same as in C# except that you use the override keyword with the virtual function implementaion in the child class. The parent class uses the same virtual keyword. Every class that overrides the virtual method will use the override keyword.
class Shape { publicvirtualvoid Draw() { Console.WriteLine("Shape.Draw") ; } }
Virtulal function can not be instatntiated. Declaring a function as virtual tells the compiler that this function is being overrided by the child one's
In C# a virtual function is always considered to be the root of virtual dispatch; that is once C# finds a virtual method it looks no further up the inheritance hierarchy. If a new virtual Sort( ) function is introduced into Window the runtime behavior of ListBox is unchanged.
When ListBox is compiled again however the compiler generates a warning:
To make the current member override that implementation add the override keyword. Otherwise add the new keyword.
To remove the warning the programmer must indicate what he intends. He can mark the ListBox Sort( ) method new to indicate that it is not an override of the virtual method in Window:
public class ListBox : Window
{
public new virtual void Sort( ) {...}
}
This action removes the warning. If on the other hand the programmer does want to override the method in Window he need only use the override keyword to make that intention explicit.
1)It is not compulsury to mark the derived/child class function with Override KeyWord while base/parent class contains a virtual method 2)Instead of Virtual we can use New Keyword 3)We will get a warning if we won't use Virtual/New keyword. 4)At the end its all depends which class object we are creating and assigned to which class reference.
Finally we are using virtual/new just for the sake of compiler.
Trust me write the code your self and test then you won't disagree.
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