I am currently building an Outlook Addin which enables users to save E-mails directly into SharePoint Online. but before the E-mails get saved, they Need to be prompted by a Windows which has a treeView of all SharePoint Folders and Subfolders of the Site URL that they have Chosen, so they can select one for the e-mails to be saved on.
I'm a beginner, but i think everybody must have been in my Position and can therefore relate. What i Need is some assistance in forms of tipps or similiar solution which could help or fully enable me to perform this Task.
All Help is Appreciated, thank you all