How to obtain folders created by the user in Outlook?

Question

I want to know if there is a better way to detect if a folder inside a store was created by the user, or if it is a default folder (created by Outlook).

I have the code below, which iterates over all the folders in a store, detecting some of the default ones.

public List<string> GetEntryIDFoldersToMonitor()
{
    OlDefaultFolders[] defaultFolders = new OlDefaultFolders[] 
    {
        OlDefaultFolders.olFolderCalendar,
        OlDefaultFolders.olFolderConflicts,
        OlDefaultFolders.olFolderContacts,
        OlDefaultFolders.olFolderDeletedItems,
        OlDefaultFolders.olFolderDrafts,
        OlDefaultFolders.olFolderJournal,
        OlDefaultFolders.olFolderJunk,
        OlDefaultFolders.olFolderLocalFailures,
        OlDefaultFolders.olFolderNotes,
        OlDefaultFolders.olFolderOutbox,
        OlDefaultFolders.olFolderRssFeeds,
        OlDefaultFolders.olFolderSentMail,
        OlDefaultFolders.olFolderServerFailures,
        OlDefaultFolders.olFolderSuggestedContacts,
        OlDefaultFolders.olFolderSyncIssues,
        OlDefaultFolders.olFolderTasks,
        OlDefaultFolders.olFolderToDo
    };

    Stores stores = Global.OutlookApp.Session.Stores;
    MAPIFolder folder = null;
    List<string> foldersToMonitor = new List<string>();    

    for (int i = 1; i < stores.Count; i++) 
    {
        Store store = stores[i];

        try
        {
            for (int j = 0; j < defaultFolders.Length; j++)
                folder = store.GetDefaultFolder(defaultFolders[j]);
        }
        catch { continue; }

        try
        {
             if (folder != null)
                 foldersToMonitor.Add(folder.EntryID);
        }
        finally
        {
            if (folder != null)
                Marshal.ReleaseComObject(folder);
        }
    }

    return foldersToMonitor;
}

I'm asking this because some of the folders take too long to load. For example, in one of our users, the default folder olServerFailures took 55 seconds to process.

Is there a better way to detect that?

Answer 1

There are no markers for identifying built-in and custom folders. You can get the folder by using the GetDefaultFolder(OlDefaultFolders) method which allows getting a Folder object that represents the default folder of the requested type for the current profile or store. So then you will be able to differentiate built-in and custom folders.

If a particular folder takes too much time for retrieving any information you just need to avoid such calls.