Specifications

3-4 Introduction
3-4
HYSYS finds extensions by looking for specific keys in the
System Registry. When an extension is registered on a
computer, information about it is added to the Registry. Upon
start-up, HYSYS scans the Registry for this information, and
adds user-specified descriptions to the appropriate lists within
the program. For instance, when a unit operation extension is
created with the description provided as “MY Unit Op”. This text
appears in the HYSYS UnitOps property view in the Available
Unit Operations pane so that the user can create instances of
them.
When the user asks for an extension to be created, HYSYS
instantiates the object and calls its Initialize method. At this
point, the extension code gains access to its Container. After the
extension has been initialized, it behaves like any other HYSYS
object of the same class.
All extensions must support at least two interfaces:
• The ExtensionObject interface
• At least one other interface particular to the type of
extension
Containers support one interface, which is particular to the type
of container.
Figure 3.1
HYSYS
Extension
Code
Container