#360 – Property Modifiers Required for Polymorphic Behavior

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

Typical combinations of modifiers for base class / derived class (assuming that the property’s name and type are the same in both the base and derived class):

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

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) – is equivalent to: (no modifier) / new
• virtual / (no modifier) – is equivalent to: virtual / new