The VBProjects Collection

This collection enables you to access a set of VB properties. This feature can be helpful if your development environment has an established process for developing software. Some of the key properties and methods of this collection are:

Filename: returns the full pathname of the group project file
Startproject: returns or sets the project that will start when users choose start menu from the run menu, click the run button, or press F5 key.
AddFromFile: This is a method that enables the users to add or open a project or group object. Its only required argument is the string representing the path of the file you want to add.
AddFromTemplate: This method enables you to add project templates into the VBProjects collection. Its only required argument is the string representing the path of the file you want to use as a template.

The Windows Collection

With the windows collection, you can access the windows such as the project and properties windows. This collection enables you to access a group of all currently open code windows and designer windows.

The IDTExtensibility Interface Object

The IDTExtensibility Interface Object exposes the public methods and properties of the extensibility model. By exposes, I mean that because you don't directly use the services, methods and properties of the underlying extensibility model, you need to invoke the methods of the model's agent, so to speak. You can think of interfaces as public agents for the private implementation of an extensibility model object you instantiate.

The Visual Basic Instance Variable

This is also known as dynamic identification variable. It identifies a particular instance of your VB session. This instance identifier enables you to have separately identifiable running instances of VB in memory.

The instance variable is of the type VBIDE.VBE. To use this variable, declare it in a class module or general module.

Please refer to Microsoft website for complete details of these packages. Please understand that I can not explain each and every detail of these packages in this short article. Lets get started with the creation of the Add-In.