Sealed classes, virtual, override, base and new — OOP Concepts in C#

11. Sealed classes, virtual, override, base and new

IntermediateMediumLesson 11 of 15

virtual — the base method can be overridden.
override — replaces a virtual/abstract member.
sealed override — stops further overriding down the chain.
sealed class — cannot be inherited (e.g. string); also lets the JIT devirtualise calls.
base.Method() — call the base implementation from the override.
new — hides a base member (rarely what you want; the compiler warns without it).
Static methods can't be virtual (except static abstract interface members in C# 11 for generic math).