PrincipalInfo.UserInfoID Field
Member identifier (ID) for an SPUser object that is initialized to -1 when the object is created, and then set to a unique value when the object is added to an SPUserCollection.
Namespace: [People Web service]
Web service reference: http://Site/_vti_bin/People.asmx
Syntax
'Declaration
Public UserInfoID As Integer
'Usage
Dim instance As PrincipalInfo
Dim value As Integer
value = instance.UserInfoID
instance.UserInfoID = value
public int UserInfoID
Remarks
A Web site has a collection of users, as well as a collection of sites which comprise the Web. The SiteUsers property of a SPWeb object represents a subset of users who are allowed to use the sites within the site collection. A smaller subset, Users, is composed of users who can use a specific site within the site collection.
When an SPUser object is created, it has an UserInfoID of -1. Adding this object to a SPUserCollection of users will give it a unique member ID, which allows an implementation to retrieve the user object by member ID as well as by e-mail address.