The LogMessagesEx collection contains LogMessage2 objects (error or informational messages) retrieved using MessageLog2.List. The collection differs from the LogMessages collection primarily in the fact that it contains LogMessage2 objects which provide more extensive properties as well as the standard LogMessage properties.
A MessageLog object is associated with the local PI-SDK message subsystem (PISDK.MessageLog) or the message subsystem of a remote or local Server (Server.MessageLog). A LogMessages collection is returned by the method MessageLog.List . A MessageLog2 object is obtained from a MessageLog object by assignment using the "set" keyword in Visual Basic to a variable of type MessageLog2; by calling QueryInterface in C or C++; or by assignments in .Net again to a variable declared as MessageLog2.