An inheritance relationship between two types is one in which one of the types derives from the other type, the latter type being called the base type. In general, a derived type's declaration space implicitly contains all of the accessible type members of its direct base type, except for the base's constructors. Some important aspects of inheritance are:
C
is derived from B
, and B
is derived from A
, then C
inherits the type members declared in B
as well as the type members declared in A
.
Visual Basic 7.0's type system is unified in the sense that all types must have a base type, except for the type Object
. Thus, Object
is the ultimate base type of all types, and all types can be converted to it.