Narrowing (Visual Basic)
Indicates that a conversion operator (CType) converts a class or structure to a type that might not be able to hold some of the possible values of the original class or structure.
Converting with the Narrowing Keyword
The conversion procedure must specify Public Shared in addition to Narrowing.
Narrowing conversions do not always succeed at run time, and can fail or incur data loss. Examples are Long to Integer, String to Date, and a base type to a derived type. This last conversion is narrowing because the base type might not contain all the members of the derived type and thus is not an instance of the derived type.
If Option Strict is On, the consuming code must use CType for all narrowing conversions.
The Narrowing keyword can be used in this context: