class A { int x; public virtual void PrintFields() { Console.WriteLine("x = {0}", x); } } class B: A { int y; public override void PrintFields() { base.PrintFields(); Console.WriteLine("y = {0}", y); } }the base.PrintFields() invocation in B invokes the PrintFields method declared in A. A base-access disables the virtual invocation mechanism and simply treats the base method as a non-virtual method. Had the invocation in B been written ((A)this).PrintFields(), it would recursively invoke the PrintFields method declared in B, not the one declared in A, since PrintFields is virtual and the run-time type of ((A)this) is B. end example] Paragraph 51 Only by including an override modifier can a method override another method. 2 In all other cases, a method with the same signature as an inherited method simply hides the inherited method. [Example: In the example
class A { public virtual void F() {} } class B: A { public virtual void F() {} // Warning, hiding inherited F() }the F method in B does not include an override modifier and therefore does not override the F method in A. Rather, the F method in B hides the method in A, and a warning is reported because the declaration does not include a new modifier. end example] [Example: In the example
class A { public virtual void F() {} } class B: A { new private void F() {} // Hides A.F within B } class C: B { public override void F() {} // Ok, overrides A.F }the F method in B hides the virtual F method inherited from A. Since the new F in B has private access, its scope only includes the class body of B and does not extend to C. Therefore, the declaration of F in C is permitted to override the F inherited from A. end example]
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