Why GUID is returned as empty?

Question

Hi,

After loading an entity from the database using LINQ-to_SQL,I pass the entity.ID(the value is GUID after loaded from the db) to a method having argument of type GUID.When I access this parameter in the method,I get an empty value,and not the GUID.Why is it so?

public sub DoSomething( ByVal userID As System.Guid)

So, when I pass entity.ID to this method,and then use userID in the method,I get an Empty value.