Adding a user to contact list
The following sample code shows how you can add a user to current user's contact list using the API.
[C#]
using CMS.Messaging;
using CMS.CMSHelper;
using CMS.SiteProvider;
using CMS.GlobalHelper;
...
// Adds administrator to CurrentUser's Contact list
UserInfo user = UserInfoProvider.GetUserInfo("administrator");
ContactListInfoProvider.AddToContactList(CMSContext.CurrentUser.UserID, user.UserID);