Binding Reports to Windows Forms Viewers
Before you can display a report in the Windows Forms Viewer, you must bind a report object to the viewer. You can do this by assigning the ReportSource property of the Windows Forms Viewer.
You may bind a report at design time to initialize a Windows Forms Viewer. You may also bind a report at runtime to support the displaying of different reports based on interactivity with the user or another Windows Form control.
The Windows Forms Viewer displays a report with temporary data at design time.
After you bind the report to a viewer, you can build and run the Windows application. The Windows Forms Viewer displays the report with real data at runtime