#350 – Method Modifiers Required for Polymorphic Behavior

There are three combinations of method modifiers that make sense, in determining whether methods in a class are virtual or non-virtual.

Typical combinations of modifiers for base class / derived class (assuming that method signature is the same in both the base and derived class):

  • (no modifier) / new – Both methods are non-virtual, derived class method hides the base class method
  • virtual / override – Both methods are virtual, support polymorphic behavior
  • virtual / new – Base class method virtual, derived class method non-virtual, derived class method hides base class method

There are two other combinations that are allowed, but result in a compiler warning indicating that you should use new in the derived class to be explicit:

  • (no modifier) / (no modifier) – effectively (no modifier) / new
  • virtual / (no modifier) – effectively virtual / new
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About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

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