I was using Delphi AfterPost Event in my Delphi applications,

AfterPost event is fired after the data on the dataset is updated but before reflected to the database. If this is converted to the Business Object terminology when the business object is updated but before the update is reflected to the database. Is there an equivalent event in StrataFrame Business Objects?

If not, could you please suggest a method to handle it manually?

Well, there are several events to handle this.  There is the BeforeSave event, AfterAddNew event, etc.  The BeforeSave will occur before the records are saved to the database.