Source1, Source2, and Source3 are read-only properties of the IMessageSendNames interface that returns the message parameter name expected by the MessageLog2.SendLogMessage method for specifying application provided source names.
Source properties of a message are provided by an application to show a chain of causation (root cause) or related items that contributed to the condition described by the message. The ProgramName property of a LogMessage or LogMessage2 object may also indicate part of the message causation. In the case of a complex application with embedded controls, the message log writer may wish to consider the ProgramName in association with providing these source message properties.
object.Source1 object. Source2 object .Source3
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.