Add event to ListView to know when it is fully loaded and ready to scroll

Is your feature request related to a problem? Please describe.
If I want to show a ListView and have it start on a certain position, let's say index 4, there is currently no way to know when the ListView is ready to be scrolled. The loaded event fires immediately when the page opens or while the ListView is still loading all the templates. Scrolling while this is happening will not work.

Right now I have to listen to the loaded event of the item template, as well as use a certain timeout of ~200 miliseconds before it's possible to scroll. This is terrible of course.

Describe the solution you'd like
Some event that we can listen on to know when all templates of the ListView are fully initialized and scrolling or any other ListView manipulation is ready to be done. Similar to RadListView which has a DataPopulated event, which may or may not be what we need.

先追蹤報告中提到的 ListView loaded 事件和 item-template 初始化流程。將要求的行為與 RadListView 的 DataPopulated 事件進行比較，然後確認新事件只有在範本完全初始化，且捲動或其他 ListView 操作準備就緒時才會觸發。