Export (0) Print
Expand All

Protected (Visual Basic)

Specifies that one or more declared programming elements are accessible only from within their own class or from a derived class.

Sometimes a programming element declared in a class contains sensitive data or restricted code, and you want to limit access to the element. However, if the class is inheritable and you expect a hierarchy of derived classes, it might be necessary for these derived classes to access the data or code. In such a case, you want the element to be accessible both from the base class and from all derived classes. To limit access to an element in this manner, you can declare it with Protected.

Rules

  • Declaration Context. You can use Protected only at class level. This means the declaration context for a Protected element must be a class, and cannot be a source file, namespace, interface, module, structure, or procedure.

  • Combined Modifiers. You can use the Protected modifier together with the Friend (Visual Basic) modifier in the same declaration. This combination makes the declared elements accessible from anywhere in the same assembly, from their own class, and from derived classes. You can specify Protected Friend only on members of classes.

Behavior

  • Access Level. All code in a class can access its elements. Code in any class that derives from a base class can access all the Protected elements of the base class. This is true for all generations of derivation. This means that a class can access Protected elements of the base class of the base class, and so on.

    Protected access is not a superset or subset of friend access.

  • Access Modifiers. The keywords that specify access level are called access modifiers. For a comparison of the access modifiers, see Access Levels in Visual Basic.

The Protected modifier can be used in these contexts:

Class Statement

Const Statement

Declare Statement

Delegate Statement

Dim Statement

Enum Statement

Event Statement

Function Statement

Interface Statement

Property Statement

Structure Statement

Sub Statement

Show:
© 2014 Microsoft