AddUser(Microsoft.SharePoint.SPUser) Method
The AddUser method of the SPGroup class adds the specified user to the cross-site group.
Parameters
user An SPUser object that represents the user.
Example
The following code example adds all the users of a subsite to a cross-site group in the site collection.
This example requires using directives (Imports in Visual Basic) for both the Microsoft.SharePoint and Microsoft.SharePoint.WebControls namespaces.
Requirements
Platforms: Microsoft Windows Server 2003
Security: Code Access Security