The Message window API uses a collection called Messages. You can use this API to access individual messages and their data and operate on the collection to add and remove messages:
Access a messages and its data:
thirdMsg = ExtAPI.Application.Messages[2] for msg in ExtAPI.Application.Messages: obj = msg.Source stringId = msg.StringID caption = msg.DisplayString scoping = msg.Location time = msg.TimeStamp objs = msg.RelatedObjects severity = msg.Severity
Add a message:
msg = Ansys.Mechanical.Application.Message("Problem!", MessageSeverityType.Error) ExtAPI.Application.Messages.Add(msg)