Yes, when using content provider from the above mentioned KB article the mapping between the physical and virtual path is a requirement for each root folder set to the RadFileExplorer's ViewPaths / UploadPaths / DeletePaths properties.
In order to assign dynamically created path to RadFileExplorer you need to dynamically create the mappings as well. You can achieve this by accessing the Page from the content provider and from the handler, e.g:
Page _page = (Page)
Then you can modify the mappings according page a property or a control.
I hope this helps.
the Telerik team
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