INFO: VB 6.0 Readme Part 10: Extensibility Issues

The information below includes the documentation and workarounds for Visual Basic 6.0. This information can also be found in the README.htm file that ships with Visual Basic 6.0 on the Visual Basic 6.0 CD-ROM. Please see the REFERENCES section of this article for a list of the Microsoft Knowledge Base articles relating to the Visual Basic 6.0 readme.

Following is a list of all parts of the readme file:

"Command-Line Safe" Add-In Behavior

You can use the Load Behavior box in the Add-In Manager to control how and when an add-in loads in Visual Basic:

• Loaded/Unloaded -- either loads or unloads a selected add-in when the box is checked or unchecked.
• Load On Startup -- indicates whether the selected add-in should load when the Visual Basic IDE is started.
• Command Line -- indicates whether an add-in should load when Visual Basic is started from a command line, either through a DOS prompt or a script.

When you select Command Line load behavior for an add-in, you may get the following warning message:

This occurs when you select an add-in for Command Line load behavior that was not declared by the author of the add-in to be "command line safe" when it was created. (This can be indicated with the Add-In Designer through a checkbox.)

"Command-line safe" means that the add-in is registered in a way to indicate that it contains no user interfaces that require user input when Visual Basic is invoked through a command-line. A user interface can interfere with the operation of unattended processes (such as build scripts).

If you don't indicate that an add-in is command-line safe (even if it is command-line safe), when a user selects your add-in and then Command Line in the Load Behavior box, they'll receive the warning message. This isn't a serious problem, but merely a warning to the user that the selected add-in might possibly contain UI elements that can pop up unexpectedly and halt their automated scripts by pausing for user input.

Manually Setting Add-In Registry Values

You can also manually set the command-line safe flag (as well as the other values) for an add-in through the Windows registry.

NOTE: You should not attempt to directly manipulate any Windows registry entries unless you are familiar with doing so. Setting an invalid registry entry can cause problems with Windows, even preventing you from being able to load Windows.

In Visual Basic 6.0, the key that holds add-in information is located in: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Visual Basic\6.0\Addins\<add- in.name>.

For Visual Basic 6.0, the LoadBehavior DWord values are:

• None = 0
• Startup = 1
• Command Line = 4
• Command Line / Startup = 5

There is also an additional DWord value that indicates whether the add-in is command-line safe: CommandLineSafe. A value of 1 indicates the add-in is command-line safe, while a value of 0 (the default) indicates that it is not command-line safe. A value of 0 is implied if you forget to check the command-line safe box in the Add-In Designer since the default value of 0 is assumed, and the add-in isn't considered command-line safe.

So, to demonstrate how to use these values to indicate that a fictitious add-in (My.Addin) is command-line safe and to have it load when Visual Basic is started by command-line, you would set the following registry values, using a tool such as RegEdit:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Visual Basic\6.0\Addins\My.Addin

Using the Add-In Designer

Visual Basic 6.0 includes a new tool, called the Add-In designer, to aid you in creating add-ins. To open it:

• Create a new add-in project.
• In the Project Explorer, under Designers, is a designer called Connect. Double-click it to activate the Add-In designer.

Unfortunately, context-sensitive help currently isn't available for the Add- In designer. Help topics are available, however. You can find the appropriate topics by searching for Add-In Designer in the MSDN index. You should see a list of three associated topics:

• "Using the Add-In Designer"
• "General Tab (Add-In Designer)"
• "Advanced Tab (Add-In Designer)"

For more information, search online, with Search titles only selected, for "Registering Add-Ins" in the MSDN Library Visual Studio 6.0 documentation.

Add-In Designer: More Information About Specifying Satellite DLL

When creating an add-in with the Add-In designer, you can specify a DLL on the Advanced tab. Be sure, however, to type only the name of the DLL file, and not its fully-qualified path. For example:

not:

Localized Satellite DLLs

If you create a localized satellite DLL, you should also create a resources directory and a locale ID directory for the satellite DLL and install the DLL in the appropriate directory. The schematic for such a path is:

For example, a satellite DLL for the German version (Locale ID = 1031) would go into the directory:

For additional information, please see the following articles in the Microsoft Knowledge Base: