C# FAQS : Class Modifiers , Static constructors , Destructors , Indexers

Class

Various class modifiers are listed below :

new
public
protected
internal
private
abstract
sealed
static

Class – new modifier

The new modifier is permitted on nested classes. It specifies that the class hides an inherited member by the same name. It is a compile-time error for the new modifier to appear on a class declaration that is not a nested class declaration.

Class – Abstract modifier

An abstract class cannot be sealed.

Class – sealed modifier

A sealed class cannot also be an abstract class.

Class – static modifier

A static class declaration is subject to the following restrictions:

· A static class may not include a sealed or abstract modifier. Note, however, that since a static class cannot be instantiated or derived from, it behaves as if it was both sealed and abstract.

· A static class may not include a class-base specification and cannot explicitly specify a base class or a list of implemented interfaces. A static class implicitly inherits from type object.

· A static class can only contain static member. Note that constants and nested types are classified as static members.

· A static class cannot have members with protected or protected internal declared accessibility.

Static constructors

Static constructors have the following properties:

A static constructor does not take access modifiers or have parameters.
A static constructor is called automatically to initialize the class before the first instance is created or any static members are referenced.
A static constructor cannot be called directly.
The user has no control on when the static constructor is executed in the program.

Destructors

Destructors cannot be defined in structs. They are only used with classes.

A class can only have one destructor.

Destructors cannot be inherited or overloaded.

Destructors cannot be called. They are invoked automatically.

A destructor does not take modifiers or have parameters.

Indexers Overview

Indexers enable objects to be indexed in a similar way to arrays.
A get accessor returns a value. A set accessor assigns a value.
The this keyword is used to define the indexers.
The value keyword is used to define the value being assigned by the set indexer.
Indexers do not have to be indexed by an integer value; it is up to you how to define the specific look-up mechanism.
Indexers can be overloaded.
Indexers can have more than one formal parameter, for example, when accessing a two-dimensional array.

C# FAQS : Class Modifiers , Static constructors , Destructors , Indexers