Many of the situations in which you previously used subreports can now be handled with data regions for better performance. The reason for the improved performance is that while every instance of each subreport must be processed by the report server, data regions do not require the server to run multiple reports. Multiple report processing can become burdensome in very large reports with a large number of subreports. Using data regions to display separate groups of data can be much more efficient in such reports. For more information, see Using Data Regions.

However, subreports still make sense when you need to nest groups of data from different data sources within a single data region, or when you can reuse a subreport in a number of reports.

Notes: If you make changes to the subreport without changing the main report, the preview window does not re-run the report unless you click the Refresh icon. If you are designing the parent report in the stand-alone Report Designer application, you must save the parent report to the same directory as the subreport for the subreport to render in the preview tab. If there are borders set on both the Subreport report item and on the body of the report hosted in it, Data Dynamics Reports does not merge the two borders. If the report hosted in the Subreport report item cannot be found or contains no rows, the border of the Subreport report item is rendered. If the hosted report is found and does contain rows, the border of the hosted report body is rendered.

Parameters

You can use parameters supplied by the parent report to filter data displayed in a subreport. You can also pass parameters to a repeating subreport nested in a data region to filter each instance. For more information, see Passing Parameters.

See Also