ECMA-334: 10.5.1 Declared accessibility

Microsoft .NET Framework, ASP.NET, Visual C# (CSharp, C Sharp, C-Sharp) Developer Training, Visual Studio

C# Language Specification

10. Basic concepts 10.5 Member access 10.5.1 Declared accessibility 10.5.2 Accessibility domains 10.5.3 Protected access for instance members 10.5.4 Accessibility constraints

© 2006 ECMA International

10.5.1 Declared accessibility

The declared accessibility of a member can be one of the following:

• Public, which is selected by including a public modifier in the member declaration. The intuitive meaning of public is "access not limited".

• Protected, which is selected by including a protected modifier in the member declaration. The intuitive meaning of protected is "access limited to the containing class or types derived from the containing class".

• Internal, which is selected by including an internal modifier in the member declaration. The intuitive meaning of internal is "access limited to this program".

• Protected internal, which is selected by including both a protected and an internal modifier in the member declaration. The intuitive meaning of protected internal is "access limited to this program or types derived from the containing class".

• Private, which is selected by including a private modifier in the member declaration. The intuitive meaning of private is "access limited to the containing type". Depending on the context in which a member declaration takes place, only certain types of declared accessibility are permitted. Furthermore, when a member declaration does not include any access modifiers, the context in which the declaration takes place determines the default declared accessibility.

• Namespaces implicitly have public declared accessibility. No access modifiers are allowed on namespace declarations.

• Types declared in compilation units or namespaces can have public or internal declared accessibility and default to internal declared accessibility.

• Class members can have any of the five kinds of declared accessibility and default to private declared accessibility. [Note: A type declared as a member of a class can have any of the five kinds of declared accessibility, whereas a type declared as a member of a namespace can have only public or internal declared accessibility. end note]

• Struct members can have public, internal, or private declared accessibility and default to private declared accessibility because structs are implicitly sealed. Struct members introduced in a struct (that is, not inherited by that struct) cannot have protected or protected internal declared accessibility. [Note: A type declared as a member of a struct can have public, internal, or private declared accessibility, whereas a type declared as a member of a namespace can have only public or internal declared accessibility. end note]

• Interface members implicitly have public declared accessibility. No access modifiers are allowed on interface member declarations.

• Enumeration members implicitly have public declared accessibility. No access modifiers are allowed on enumeration member declarations.