Does anyone have any advice on how to fill the elements tree from a database via ASP.NET?
The approach is not different from any other server side technology.
1. Move the items structure from the outside tree_items.js file into main HTML/ASP document by replacing the link with the script block containing the definition of the items variable.
2. Write the ASP code that generates the text of the items variable and put it in place of the static data.
Numerous code samples available in this forum and from third parties. If you end up creating own feel free to publish it here.