Is C# method sealed or virtual by default?

Question

I know the definitions of virtual and sealed keywords, but if you don't use either of them with a method, can the method be overriden by default?

I am coming from vb.net background. It goes like this in vb.net (from MSDN):

If the Overridable or NotOverridable modifier is not specified, the default setting depends on whether the property or method overrides a base class property or method. If the property or method overrides a base class property or method, the default setting is Overridable; otherwise, it is NotOverridable.

I just want to know if that's also true in C#.

Answer 1

默认情况下，C＃中的方法不是虚拟的。

Answer 2

No it cannot. You need to explicitly mark a method as virtual to allow it to be overridden in derived classes.

What you can do however, is hide a method by using the new keyword. (MSDN Documentation)

The sealed keyword is used on both class definitions and methods. It disallows inheriting from a class or overriding of a method. By default, if you don't use this keyword, others will be able to inherit from your class. ( MSDN Documentation )

Answer 3

No. Unlike Java, in C# methods are not virtual by default. They neither are sealed , but you cannot override them, because they are normal methods.

Answer 4

No, you cannot override a non-virtual method. The new keyword only hides the base class implementation and is not a good practice.

Discussion on this with Anders Hejlsberg here