You can use one of the following approaches to load the dashboard to the Dashboard Viewer.
Create a dashboard in the DashboardDesigner and save its definition to an XML file. To open the saved dashboard, click the DashboardViewer's smart tag button and select Load Dashboard... in the Dashboard Source drop-down menu, to locate the required dashboard XML file.
Create a dashboard in the Visual Studio Dashboard Designer. To open the project dashboard, click the control's smart tag button, click the Dashboard Source drop-down arrow, and select the dashboard listed under Project Dashboards.
You can assign the type of the created dashboard to the DashboardViewer.DashboardSource property.