Accessibility Levels (C# Reference)

 

Updated: July 20, 2015

System_CAPS_ICON_note.jpg Note

For the latest documentation on C#, visit the C# Guide on docs.microsoft.com.

Use the access modifiers, public, protected, internal, or private, to specify one of the following declared accessibility levels for members.

Declared accessibilityMeaning
publicAccess is not restricted.
protectedAccess is limited to the containing class or types derived from the containing class.
internalAccess is limited to the current assembly.
protected internalAccess is limited to the current assembly or types derived from the containing class.
privateAccess is limited to the containing type.

Only one access modifier is allowed for a member or type, except when you use the protected internal combination.

Access modifiers are not allowed on namespaces. Namespaces have no access restrictions.

Depending on the context in which a member declaration occurs, only certain declared accessibilities are permitted. If no access modifier is specified in a member declaration, a default accessibility is used.

Top-level types, which are not nested in other types, can only have internal or public accessibility. The default accessibility for these types is internal.

Nested types, which are members of other types, can have declared accessibilities as indicated in the following table.

Members ofDefault member accessibilityAllowed declared accessibility of the member
enumpublicNone
classprivatepublic

 protected

 internal

 private

 protected internal
interfacepublicNone
structprivatepublic

 internal

 private

The accessibility of a nested type depends on its accessibility domain, which is determined by both the declared accessibility of the member and the accessibility domain of the immediately containing type. However, the accessibility domain of a nested type cannot exceed that of the containing type.

For more information, see the C# Language Specification. The language specification is the definitive source for C# syntax and usage.

C# Reference
C# Programming Guide
C# Keywords
Access Modifiers
Accessibility Domain
Restrictions on Using Accessibility Levels
Access Modifiers
public
private
protected
internal

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