I have an app where I need the maplayer ElementPrerender to fire on demand. What do I need to do to the XamWebMap object that continas the maplayer to cause this to happen? This fires the first time on load with no problem.
Could you explain in more detail what you are trying to accomplish? There are various things that you can do to cause this event to fire. If you, for example, change the ToolTip on the map layer, or most settings that would affect every element in the layer the layer will try to re-render all the elements. But it will only fire ElementPrerender for elements that are not culled from view (i.e. the elements it is actually going to render), so keep this in mind.
-Graham