TreeList - Editing via Context Menu

This example illustrates how to edit the MVC TreeList via a separate PopupMenu.
The main implementation details:
- Store the Parent Node Key data within a node by handing the TreeListSettings.HtmlRowPrepared event;
- Handle the client-side ASPxClientTreeList.ContextMenu event, show the context menu via the client-side ASPxClientPopupMenu.ShowAtPos method, and store information about a hovered node key/parent key;
- Handle the client-side ASPxClientMenuBase.ItemClick event and invoke the corresponding CRUD command via ASPxTreeList's client-side API.