Outlook VSTO NewMailEx is not firing for new storage - events

Question

I am developing an Outlook plugin and faced with the problem when my callback NewMailEx is not called for a newly added storage.
My code looks like the next:
private void ThisAddIn_Startup(object sender, System.EventArgs e)
{
Application.ItemSend += Application_ItemSend;
Application.NewMailEx += Application_NewMailEx;
}
private void Application_NewMailEx(string EntryIDCollection)
{
logger.Debug("Received e-mail with ID: {0}", EntryIDCollection);
var outlook_namespace = Application.GetNamespace("MAPI");
dynamic item = outlook_namespace.GetItemFromID(EntryIDCollection);
if (!(item is Outlook.MailItem))
return;
// do some stuff with mail
}
I also tried to subscribe for a new storage:
{
Application.Session.Stores.StoreAdd += Stores_StoreAdd;
}
private void Stores_StoreAdd(Outlook.Store store)
{
logger.Info("New store is added: " + store.DisplayName);
Outlook.MAPIFolder rootFolder = store.GetRootFolder();
Outlook.MAPIFolder inbox = store.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox);
inbox.Items.ItemAdd += items_ItemAdd;
}
private void items_ItemAdd(object item)
{
if (item is Outlook.MailItem)
{
Outlook.MailItem mail = item as Outlook.MailItem;
// do some stuff with mail
}
}
But ItemAdd is called only for items during the synchronization. For a new mails neither NewMailEx nor ItemAdd are called.
But after the restart everything works and NewMailEx works as usual.
Do you have any ideas how to fix it or some workaround?

Answer 1

Your items_ItemAdd event handler will never fire because you set up the event handler on an implicit variable created by the compiler on the line inbox.Items.ItemAdd += items_ItemAdd. You need to save Items object in a dedicated variabler (or event better a List<Items>) to make sure it stays alive and GC never releases it.