Virtual function in c#

hi,

Can anybod briefly explain about "what is virtual function?" and how to write a virtual function in c#.
Give me one example of writing one virtual function.
And what is the basic use of that.

Thanks in Advance.

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.

Code:

---

class Shape
{
    public virtual void Draw()
    {
        Console.WriteLine("Shape.Draw")    ;
    }
}

class Rectangle : Shape

{
    public override void Draw()
    {
        Console.WriteLine("Rectangle.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

Virtual Keyword force the method to be implemented in the derived class. When we call that method, the method in the drived class will be executed. not method in the base class. We can provide new implementation with help override keyword