Accessibility Levels (C# Reference)

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

Declared accessibility Meaning
public Access is not restricted.
protected Access is limited to the containing class or types derived from the containing class.
internal Access is limited to the current assembly.
protected internal Access is limited to the current assembly or types derived from the containing class.
private Access is limited to the containing type.
private protected Access is limited to the containing class or types derived from the containing class within the current assembly.

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

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 of Default member accessibility Allowed declared accessibility of the member
enum public None
class private public

protected

internal

private

protected internal

private protected
interface public public

protected

internal

private*

protected internal

private protected
struct private public

internal

private

* An interface member with private accessibility must have a default implementation.

Note

If a class or struct is modified with the record keyword modifier, then the same access modifiers are allowed.
Also, with the record modifier the default member accessibility is still private both for class and the struct.

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.

C# Language Specification

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

See also