This example shows how to override an initial or user-defined dashboard parameter value by changing it in the DashboardControl.CustomParameters event handler. The effective parameter value is hidden from the end-user, and if you set the DashboardParameter.Visible property to false, the parameter itself will also be hidden.

To accomplish this task, a parameter named parameterState is added to the dashboard. It has a default value and a list of values to show in a look-up editor. A Dashboard Parameters dialog displays the values and allows the end-user to select a parameter value in the list.

By handling the DashboardControl.CustomParameters event, we can validate the parameter value and ignore the value provided by the end-user. To accomplish this, source data is filtered using a parameterState parameter. The value of this parameter is changed at runtime by handling the CustomParameters event which is raised before the dashboard sends a query to a database. Thus, only the value passed in the DashboardControl.CustomParameters event is in effect.