You can make a distinguished field in schema for the file. Distinguished fields are usefull when you want to make decisions or to manipulate data in an orchestration. The pipeline disassembler will insert a
Written property into the message context for items that are marked as a distinguished field. This is usefull if you are working with an orchestration to process the file. Other option is to use a promoted property, as criteria for message
routing. Which is available in an orchestration too. Files that need to be processed are routed to a destination, where this happens (i.e. orchestration or target system). You can create promote properties in schema belonging file or Tariq suggest not in schema,
but in custom pipeline component. Note here that Distinguished fields and promoted properties have to always get Min/Max Occurs = 1. See also MSDN
About Message Context Properties. You have a few options here to your scenario.
MCTS BizTalk Server
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