KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q149429: INFO: What Is an OCA file?

Article: Q149429
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,5.0
Operating System(s): 
Keyword(s): kbnokeyword kbVBp400 kbVBp500 kbVBp600
Last Modified: 11-JAN-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 
- Microsoft Visual Basic Learning Edition for Windows, version 5.0 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
-------------------------------------------------------------------------------

SUMMARY
=======

For every custom control file (.OCX) that Visual Basic uses, there is an
accompanying .OCA file of the same file name. For example, GRAPH16.OCX has an
accompanying .OCA file called GRAPH16.OCA. An .OCA file is a binary file that
functions as both an extended type library file and a cache for the custom
control file.

MORE INFORMATION
================

A type library is a file or component within another file that contains OLE
Automation standard descriptions of exposed objects, properties, and methods.
The actual working type library for a custom control used in Visual Basic is a
combination of the type library of the control itself and the additional
properties provided by the framework that wrap the control.

Some of the properties of the control are provided by the framework and some by
the control itself. Programmatically, the properties from the framework and the
control all appear as properties of the control.

In order for these properties to appear, Visual Basic creates an extended type
library when the control is loaded into the toolbox. Because the process of
reading the control's type library and creating the extended type library is
time consuming, Visual Basic caches the extended type library information into
an OCA file.

If you delete the OCA file for a control Visual Basic recognized, Visual Basic
will recreate the .OCA file when you load a project requiring the control. This
recreation process comes with a time penalty.

Additional query words: files

======================================================================
Keywords          : kbnokeyword kbVBp400 kbVBp500 kbVBp600 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVBA500 kbVB500 kbVB400Search kbVB400 kbZNotKeyword3 kbVB16bitSearch
Version           : WINDOWS:4.0,5.0
Issue type        : kbinfo

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.