Advanced Report Design - Professional SQL Server 2005 Reporting Services - page 208

Drill-Down Reports
A drill-down report is an interactive report that allows the user to expand and collapse grouped sections
to discover more detail as needed. In recent years, users have become accustomed to this type of tree
view navigation in common software, so it has become an intuitive user interface metaphor. Interactive
reports give users more options and reduce unnecessary screen space used by data that users need not
view. They can drill down further as suits their need to view more specific details. Drill-down reports
are designed to be interactive, but they usually work well on the page. Different report-rendering for-
mats treat drill-down reports a little differently. In HTML and Excel, reports will behave as they do in
the report designer. However, PDF and image-rendered reports don't support the dynamic drill-down
functionality. When exported from the Report Manager, these reports will have sections expanded and
collapsed as they were at the time they were exported.
The magic of drill-down reports is that rows and sections are simply hidden and displayed based on a
toggle item. This means that a value item (like a text box) is used to toggle the hidden property of rows
and other report items. A plus sign (+) is displayed to the left of the toggle item. Each time the user clicks
the icon, the hidden property for the associated row items is toggled between the value True and False,
and the icon toggles between a plus (+) and minus (-) sign. The rows must also be set up to collapse
when they are hidden.
Using the Products and Categories report from the previous example, the detail row and SubCategory
header row must be hidden and set up to toggle. As drill-down visibility is managed at the group level,
you need to define a group for the detail row. Select the detail row using the row selector, right-click, and
choose Edit Group to show the Grouping and Sorting Properties dialog. Select =Fields!ProductName
.Value from the drop-down list in the first row of the Expression list box, as shown in Figure 6-33.
Figure 6-33