The .NET interface for a collection of objects with a common key
The IGrouping interface, introduced in .net-3.5 as part of linq, represents "a collection of objects with a common key".
It is typically encountered as a result of a GroupBy operation - for example
IGrouping<System.Reflection.MemberTypes, System.Reflection.MemberInfo> group =
typeof(String).GetMembers().
GroupBy(member => member.MemberType).
First();
The members of the interface are used when handling results of any linq GroupBy operation. Questions that deal with handling the results of such GroupBy operations, or which otherwise construct objects that implement this interface, are expected to have this tag.
The interface itself defines available methods and properties which generally involve working with the objects inside the collection (or group).
