Report Solution Patterns and Recipes - Professional SQL Server 2005 Reporting Services - page 306

Figure 7-44
A group is defined in the table based on an expression that uses this parameter to resolve the field value.
In the report header, I want to show the field name, and in the group header, I want to show the actual
field value. To return the friendly field name that was displayed in the parameter drop-down list, I refer
to the Label property of the parameter. You can see in Figure 7-45 that the field value is displayed using
the compound expression: =Fields(Parameters!GroupBy.Value).Value . The inner reference
(Parameters!GroupBy.Value) is resolved first to return the field name, which is passed to the outer
expression (Fields( <field name> ).Value ) to resolve the field value from the field name. I have
found this technique useful in many different reports.
Figure 7-45
Figure 7-46 shows the properties for the table group. The same expression you saw in the previous fig-
ure is used to define the group. On the Sorting tab of the Grouping and Sorting Properties dialog, shown
in Figure 7-47, the sorting expression is set to match the group expression.