17.10.4 Default constructors

If a class contains no instance constructor declarations, a default instance

constructor is automatically provided.

That default constructor simply invokes the parameterless constructor of

the direct base class. If the direct base

class does not have an accessible parameterless instance constructor, a

compile-time error occurs. If the class is

abstract then the declared accessibility for the default constructor is

protected. Otherwise, the declared

accessibility for the default constructor is public. [Note: Thus, the

default constructor is always of the form

protected C(): base() {}

or

public C(): base() {}

where C is the name of the class. end note]

[Example: In the example

class Message

{

object sender;

string text;

}

a default constructor is provided because the class contains no instance

constructor declarations. Thus, the

example is precisely equivalent to

class Message

{

object sender;

string text;

C# LANGUAGE SPECIFICATION

262

public Message(): base() {}

}

end example]