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RadEditor for ASP.NET AJAX for DNN
RadEditorProvider does not have a separate property to specify where content could be uploaded. It uses the DotNetNuke core functions to verify whether a user has write permissions to a specific folder. So in effect you only need to include an "ImagesPaths" property. The provider will decide to which paths from the list the user can upload.
The other difference from a normal editor is the "*PortalRoot*" path. It specifies the root folder of the portal, from which the editor is opened.
DotNetNuke keeps the folder and file structure of a portal in its database. When you manually copy content to your portal folder, the database and the folder get out of sync. Normally after you change the folder structure of your portal, you should go to Admin>File Manager and click the Synchronize Database And File System link. This will insert information about the new folders in the database and ensure that RadEditor will be working correctly. An exception "Directory already exists." will be thrown if you try to use the editor when the database and file system are not synchronized.
If you set ImagesPaths="images, *PortalRoot*", the user will be able to select images from "DotNetNuke/Portals/0/" and "DotNetNuke/Portals/0/images/", where "DotNetNuke" is the root folder of your DotNetNuke project.