Static (Member)

Static methods do not have an implicit This instance argument passed to them. This allows them to be used like normal non-member procedures (for example with callback procedure pointers). An advantage of Static methods are that they are encapsulated in the typename namespace, and therefore have the ability to access the Private or Protected members or methods of instances of typename.

Static methods can be called directly anywhere in code, like normal non-member procedures, or on objects of type typename, similar to non-static methods, however either way there is no implicit or explicit This (or explicit Base) access possible from within a static method.

For member procedures with a Static declaration, Static may also be specified on the corresponding procedure bodies, for improved code readability.

Static member variables are created and initialized only once independently of any object construction, in contrast to non-static ("instance") member variables which are created again and again for each separate object. Static members are always Shared, even if Shared was not specified in the declaration. Thus, Static member variables are similar to global variables, except that they are declared in a Type namespace.

Each Static member variable declared in a Type must be explicitly allocated somewhere outside the type by using a Dim statement. The declaration inside the Type is the prototype that is visible to every module seeing the Type declaration. The definition outside the Type allocates and optionally initializes the Static member variable. There can only be one definition per Static member variable: it can only be allocated in a single module, not in multiple ones. This is the same as for Extern variables.

A Static member variable is subject to member access control except for its definition outside the Type. If a private Static member variable is to be explicitly initialized outside the Type's member procedures, an initializer must be provided with the definition.