OriginatingHost is an optional read-only property of the IMessageSendNames interface that returns the name expected by the MessaageLog2.SendLogMessage method for specifying by the user defined message property OriginatingHost.
An originating host represents the machine sending a message as determined by an application. The MessageLog2.SendLogMessage method will automatically add the ProcessHost to any log message sent to a PI server's Message log (remote messages). When sending messages to the local log it is assumed the process host is the same as the host of the PI Message subsystem and this parameter is not logged. However in some cases, such as an application server, the machine where the application is running (the process host) may not be the machine that the message pertains to. In this case the application may choose to use the OriginatingHost property of a message to clearly define the source of the message.
The object placeholder is an object expression that evaluates to a IMessageSendNames interface.
The IMessageSendNames interface can be obtained directly from the MessageLog2.MessageSendNames property or by using QueryInterface (assignment, in VB, casting in .Net) on a MessageLog or MessageLog2 object.
When adding to the NamedValues collection, the IMessageSendNames interface acts with Intellisense to show the available parameter options and ensures only names that are supported are used.