.NET Metadata provides an overloaded extension method (Meta) on all objects,
which allows data to be stored for any instance of any reference type.
It is for the .NET Framework 4.0 or later.
An Example
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using org.bovinegenius.Metadata;
Hashtable money = new Hashtable();
money["Fred"] = 300.00;
money["Sam"] = 450.00;
money["George"] = 7000.00;
// Store metadata about where this Hashtable came from
money.Meta("Origin", "Code");
Hashtable people = DB.GetPeople();
// Store metadata saying this Hashtable came from the database
people.Meta("Origin", "Database");
var moneyOrigin = money.Meta("Origin"); // "Code"
var peopleOrigin = people.Meta("Origin"); // "Database"