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Understanding Member Shadowing

C# provides a facility that is the logical opposite of method overriding termed shadowing. Formally

speaking, if a derived class defines a member that is identical to a member defined in a base class,

the derived class has 

shadowed the parent’s version. In the real world, the possibility of this occur-

ring is the greatest when you are subclassing from a class you (or your team) did not create

yourselves (for example, if you purchase a third-party .NET software package).

For the sake of illustration, assume you receive a class named ThreeDCircle from a coworker

(or classmate) that defines a subroutine named Draw() taking no arguments:

class ThreeDCircle

{

public void Draw()

{

Console.WriteLine("Drawing a 3D Circle");

}

}

You figure that a ThreeDCircle “is-a” Circle, so you derive from your existing Circle type:

class ThreeDCircle : Circle

{

public void Draw()

{

Console.WriteLine("Drawing a 3D Circle");

}

}

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