.NET Framework 4.5
Gets or sets a semicolon-delimited set of control identifiers contained within the current page or user control used to vary the current cache entry.
Assembly: System.Web (in System.Web.dll)
Property ValueType: System.String
A semicolon-separated list of strings used to vary an entry's output cache. The property is set to fully qualified control identifiers, where the identifier is a concatenation of control IDs starting from the top-level parent control and delimited with a dollar sign ($) character.