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:
- In an existing OLE server project, press F2 to display the Object
Browser.
- 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.
- With the class module selected, press the Options button.
- 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.
- 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.