Understanding the Report Application Server Bridge

An important change has occurred to the report engine object model in version 10 of Crystal Reports. In fact, you might not even have realized this change has taken place after using Crystal Reports 10 for quite some time; however, it's important to understand. The object model that was previously supplied with the various .NET offerings that Crystal Decisions has produced has talked directly to the Crystal Reports print engine. In version 10, the object model talks to the Report Application Server, and then in turn to the Crystal Reports engine. Although there is no immediate noticeable changes to the way the engine operates, this is an important change for two key reasons:

• The Report Application Server exposes more functionality than the report engine object model discussed thus far, and this additional functionality can now be leveraged from the report engine object model.

• Because the Report Application Server is a part of the Crystal Enterprise framework, any application using the Crystal Reports 10 report engine object model and viewers is now very easily upgradeable to Crystal Enterprise.

As for the first point, the Report Application Server's API is available through the standard report engine object model. To access it, use the ReportClientDocument property of the ReportDocument object. The ReportClientDocument is the equivalent to the ReportDocument for the Report Application Server. It includes the capability to not only open and change reports, but also to create reports from scratch, add new report objects, add new data sources, and so on. For more information on the Report Application Server, consult Chapter 31, “Introduction to Crystal Enterprise Embedded.”