Load a large number of records into a VB.NET treeview control quickly

I want to load 20 million records in a treeview control with parent child Hierarchy order

for example

- Groupa
    - a1  
    - a2
    - a3
    - Groupa1
      - a11
      - a12
      - a13
 - Groupb开发者_开发技巧
    - b1  
    - b2
    - b3

Why don't you lazy load the tree?

Initially only load the nodes at the bottom level. Children nodes then only need loading when the parent node is expanded.