Geospatial Portal SDK provides the Dynamic Feature Events API to override/register different events for vector features. The following extension highlights this API to render charts as MapTips (ToolTips) on mouse hover over the vector features.
In the aspx page add the following div element on which the chart is rendered.
Place the following code snippet inside a js file and reference it in the aspx page. The code snippet is written to work on the US Sample Data WFS (http://demo.hexagongeospatial.com/GWM_WFS_NonTransactional/service.svc/get). To use any other WFS sources change the code accordingly wherever there is reference to the feature attribute information.