In the report designers, you are not working with the actual data but a representation of the data indicated by the field name or expression. When you want to see the actual data displayed in the context of the report you design, you can preview the data from the underlying database displayed in the report layout. Switching between designing and running your report allows you to adjust its design and see the results immediately. To view the report you have designed:
Switch to Preview mode.
Use any of the report viewers in a standalone application. For more information see Using Telerik Reporting in Applications.