VB Shell Programming

Registry

Here’s the big question. How do we distinguish our band object as an Explorer band versus a Communication band or a Desk band? We do this by assigning our component to the Explorer Band component category. Component categories are used to group functionality. For instance, when you create an ActiveX DLL component in Visual Basic, a registry setting is added that specifies the component to be in the category “Automation Objects.” Verify this for yourself. Look up any of the CLSIDs for the components we have created in this book under its HKEY_CLASSES_ROOT\CLSID entry. You will find a subkey named Implemented Categories. Here you will find the following key:

{40FC6ED5-2438-11CF-A3DB-080036F12502}

Now, search for this key under the following key:

HKEY_CLASSES_ROOT\Component Categories

You will find that this CLSID represents a category called “Automation Objects.” OLE View groups components by category. Take a look. If you ever work on a project containing several components that implement common interfaces, you might want to create your own component category. It’s as simple as creating a GUID with GUIDGEN.EXE and adding it to:

HKEY_CLASSES_ROOT\Component Categories

This mechanism allows the shell to quickly find the components it requires, in our case, Explorer Bands. Table 13.3 lists the CLSIDs for the three types of band objects.

Table 13-3. CLSIDs of Band Categories

Band Category	CLSID
Desk Band	{00021492-0000-0000-C000-000000000046}
Explorer Band	{00021493-0000-0000-C000-000000000046} ...