Report Solution Patterns and Recipes - Professional SQL Server 2005 Reporting Services - page 312

Figure 7-53
Next to each text box, I have placed an image item. Its value will correspond to the SortDirection
parameter if the SortField value matches that table column. Figure 7-54 shows the Image item
Value property expression. According to this logic, if the SortField parameter value matches this
table column (SalesTerritoryName), then the appropriate arrow icon will be displayed based on the
SortDirection parameter value. If the SortField parameter is for another column, the “no_arrow”
white-space image is used.
In the Sorting properties for the table, shown in Figure 7-55, two expressions are used to test the
SortDirection parameter. If the parameter value is “Ascending,” then the first expression (on the
Ascending line) returns the field value for the field name contained in the SortField parameter.
Returning an empty string ( “” ) causes that sort expression to be ignored and enables the other
(Ascending or Descending) expression.