the order of the parameters, the name of the property
or method, or the data type of the return value.
When you create the executable for a version-identical
upgrade, you can use the same file name for the
executable. Visual Basic uses the same version number
for the type library.
Important When you release a new version of your
component with a version-identical or
version-compatible interface, and retain the same file
name for the executable, you should always use the
Make tab of the Project Properties dialog box to
increment the file version number. This ensures that
the setup programs for applications that use your
component will replace old versions during setup.
When you enhance your component by adding new classes,
or new properties and methods to existing classes, you
can continue to use the same name for your executable.
As long as you make no changes to existing properties
and methods, Visual Basic updates the version number
of the type library but keeps it compatible with the
old version number.
Client applications that are built using the new
version of your component will compile with the new
version number, and can make use of all the new
features. They cannot be used with earlier versions of
your component, however, because type library versions
are only upward-compatible.
As with version-identical releases, remember to
increment the file version number of the executable.
Sometimes design decisions made in an earlier version
of a component fail to anticipate future needs. If you
want the code in the component to be useful in new
development projects, you have to change the
For example, the CupsPerAnnum parameter of the Coffee
method might be implemented as an Integer in the first
version of a component. It may become apparent, after
the component has been in use for some time, that some
clients need to pass a larger value than can be
contained in an Integer.
Changing the declaration of a method is only one of
several actions that will cause Visual Basic to make
the version number of the type library incompatible,
rendering the new version unusable with client
applications compiled with earlier versions. The
following changes will cause a version
Changing the Project Name field on the General tab
of the Project Properties dialog box.
Changing the Name property of any class module whose
Public property is True (controls), or whose
Instancing property is not Private (class modules).
Deleting a public class module, or setting its
Instancing property to Private.
Deleting a public variable, procedure, or Property
procedure from a public class module or control, or
changing it to Private or Friend.
Changing the name or data type of a public variable,
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