Hello Martin Borggio,
You can use RadTreeView for this purpose.
Here is a link to the demo page for this control: http://demos.telerik.com/aspnet-ajax/treeview/examples/overview/defaultcs.aspx
About the node expand - you can use one of our Load On Demand functionalities implemented for RadTreeView, in which only the treeView is being updated and the rest of the page remains the same (that would be ExpandMode ServerSideCallback or ExpandMode WebService).
Here is a link to the demo page for this functionality: http://demos.telerik.com/aspnet-ajax/treeview/examples/programming/loadondemandmodes/defaultcs.aspx
Also, there is another control that can make sense for such scenario - RadFileExplorer.
Here is the demo page this control: http://demos.telerik.com/aspnet-ajax/fileexplorer/examples/overview/defaultcs.aspx
Please, go through these links and if there is something else that you need to ask - please, don't hesitate to write to our team again! We will be happy to help!
Hope this is helpful for you!
the Telerik team
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