property Messages [index: Integer]: TIdMessage;

Messages is an Integer indexed TIdMessage property that provides access to the TIdMessage contained in a collection item. Index values must be in the range 0 to Count-1. 

Messages is the default property for the collection. 

The following statements are equivalent, and return the same TIdMessage instance from the collection: 

   // AMailbox: TIdMailbox
   MAgent.RenderPreview(AMailbox.MessageList.Messages[i]);
   MAgent.RenderPreview(AMailbox.MessageList[i]);