Files to look at:
Web Dashboard - How to customize a dashboard before displaying it in a browser
This example demonstrates how to handle the ASPxDashboard.DashboardLoading event that is raised when a dashboard is loaded. In the event handler, you can edit the loaded dashboard and provide the updated version to the ASPxDashboard control. In this example, the default parameter value is set and the data source query to filter displayed data is customized at runtime.