This is a TreeListView, running in virtual mode. the data is never stored within the control.
Latest Tree View Articles
Thanks to ASP.NET 2.0's built-in TreeView control, you can give your Web site a professional-looking navigation system that displays hierarchical data—without having to write lots of code and script.
Learn to get around the limitation for the maximum value of the .NET TreeView's ItemHeight property.
Latest CodeGuru Developer Columns
Learn to implement exception handling mechanism in C++.
Computer software used to be written for serial computation by a serial computer. Circumvent that concept and work in parallel streams.
With .NET Standard, you only have to master one platform, which will be able to run on all .NET platforms.
It's good practice to use code metrics to validate code; it will improve code quality and make your application maintainable and less complex.