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Q149047: How to Specify Informational Text for VB4 OLE Servers

Article: Q149047
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.00 | 4.00
Operating System(s): 
Keyword(s): 
Last Modified: 11-JAN-2001

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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 
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SUMMARY
=======

OLE automation servers created with Visual Basic 4.0 can expose informational
text in various places to enable OLE automation clients to identify and use them
easily. The actual strings that are viewable from an OLE automation client can
be set within the Visual Basic OLE server project. This article outlines the
places that the information should be entered and modified, as well as where it
will appear in external locations.

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

The two locations within Visual Basic where these settings can be changed are
the Project tab of the Options dialog box and the Member Options dialog box
available from the Object Browser. The Project tab contains both Project Name
and Application Description text boxes. If a class module is selected in the
Object Browser, pressing the Options button will display a dialog box containing
a Description text box.

Project Name in Options
-----------------------

The Project Name field in the Options dialog box contains the first part of what
is known as the programmatic ID or ProgID of any class exposed by the OLE
server. The class name (as specified in the Properties window for the class
module) provides the second part of the ProgID.

For example, assuming the string MyOLEServerProj was entered in the Project Name
field, and a public class module existed in that project with the name
MyPublicClass, then the ProgID for that class would be:

     MyOLEServerProj.MyPublicClass

A key with this entry will be made in the HKEY_CLASSES_ROOT predefined key in the
registry when the project is compiled to an executable or run in the design
environment. OLE uses this registry key to determine what server to use when
anyone attempts to create an object from an OLE automation client. If multiple
public classes exist in a project, there will be multiple entries made to the
registry containing the same initial identifier. For example, given
MyPublicClass1, MyPublicClass2, and MyPublicClass3, the following three keys
would be created in the registry:

     MyOLEServerProj.MyPublicClass1
     MyOLEServerProj.MyPublicClass2
     MyOLEServerProj.MyPublicClass3

The Project Name string is also used as the name of the library or project in the
Libraries/Projects drop-down combo box displayed by the Object Browser.

Application Description in Options
----------------------------------

The Application Description field in the Options dialog box provides a location
to specify a single string identifying the OLE server. The string entered in the
Application Description text box will be displayed in the References dialog box
by Visual Basic 4.0 (and other VBA clients). This string will be displayed as an
entry in the Available References list box and as the title of the frame below
the list box that shows location and language information for the selected OLE
server. If the Application Description text box has been left blank, Visual
Basic will use the string in the Project Name field as a replacement. The
Application Description string will also be used by the Object Browser as the
description for the OLE server in the Libraries/Projects drop-down combo box.

The application description information is compiled into the type library that is
part of each server EXE or DLL generated by Visual Basic 4.0. Any client that is
written to query type libraries for this information will be able to retrieve
and display it. When the References dialog box is opened, Visual Basic is doing
exactly that: its running through all registered classes and retrieving this
information for display in the References dialog box.

Example Application Description Strings
---------------------------------------

  Microsoft DAO 3.0 Object Library
  Microsoft Visual Basic 4.0 Development Environment
  OLE/Messaging 1.0 Object Library

Additional examples can be seen by simply viewing the entries in the References
dialog box.

Description in Object Browser Options Dialog Box
------------------------------------------------

After displaying the Object Browser and selecting a class module in the
Classes/Modules list box, the button on the Object Browser labeled Options is
enabled. Pressing this button displays the Member Options dialog box. This
dialog box can be used to set and modify the descriptions for both a class
module in general and also specifically for each public member (function,
subroutine, or property) of the class module.

This information will be used by the Object Browser to display a help string for
the selected class or the selected member of a class. This string is displayed
at the bottom of the Object Browser dialog box.

Follow these steps to see an example of this behavior:

1. In an existing OLE server project, press F2 to display the Object Browser.

2. In the Libraries/Projects drop-down combo box, select a public class module.
  If no previous description has been entered, the area to the right of the
  question mark button at the bottom of the Object Browser will be blank.

3. With the class module selected, press the Options button.

4. Enter a suitable text string in the Description text box of the Member
  Options dialog box. Notice that the Member Name is listed as the name of the
  public class. If a class module AND a public function, subroutine, or
  property, had been selected in step 2, Member Name would be the name of this
  public member. In this case the description entered would apply only to the
  selected member.

5. Choose OK to return to the Object Browser. Notice that the string entered in
  step 4 now appears next to the question mark button at the bottom of the
  Object Browser dialog box. Any OLE automation client can access and display
  this information.

Additionally, where Visual Basic 4.0 add-ins are concerned, the description for a
public class module entered in the Member Options dialog box is the description
that will be displayed in the Available Add-Ins list box displayed by the Add-In
Manager.


The Help Context ID field in the Member options dialog box can be utilized to
link a specific part of a help file to each class module and public member. The
entry listed in the Help File label is whatever help file has been specified in
the Help File section of the Project Tab of the Options dialog box. For more
information on how to provide help in this manner, see the online help and the
Visual Basic 4.0 manuals.

Additional query words: 4.00 vb4win vb4all listbox combobox dropdown

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Keywords          :  
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : 4.00 | 4.00

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