The OriginatingPIUser property of the LogMessage2 object is a Read-Only string that represents the authenticated PI user sending a message as determined by an application. The MessageLog2.SendLogMessage method will automatically add the ProcessPIUser to any log message sent to a PI server's Message log (remote messages). When sending messages to the local log the PI-SDK can not determine the proper PI user so this property is not added automatically though can be explicitly sent by an application. In some cases, such as an application server, the PI user associated with the application's process may not be the PI user that the message pertains to. In this case the application may choose to use the OriginatingPIUser property of a message to clearly define the authenticated PI user sending the message or related to the message's contents.
The object placeholder is an object expression that evaluates to a LogMessage2 object.