How to iterate over all MailItems items of specific Outlook subfolders

Question

I am working on an Outlook 2007 add-in. I found that some code was sorting through all the folders, but I couldn’t figure out how to loop inside any given folder to check MailItem objects (ultimately, I want to save emails elsewhere and change the .Subject property).

Here is what I still have:

private void btnFolderWalk_Click(object sender, EventArgs e) { // Retrieve the name of the top-level folder (Inbox) , for // the purposes of this demonstration. Outlook.Folder inbox = Application.Session.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox) as Outlook.Folder; // Cast the MAPI folder returned as an Outlook folder // Retrieve a reference to the top-level folder. if (inbox != null) { Outlook.Folder parent = inbox.Parent as Outlook.Folder; // the mailbox itself if (parent != null) { RecurseThroughFolders(parent, 0); } } } private void RecurseThroughFolders(Outlook.Folder theRootFolder, int depth) { if (theRootFolder.DefaultItemType != Outlook.OlItemType.olMailItem) { return; } lbMail.Items.Add(theRootFolder.FolderPath); foreach (Object item in theRootFolder.Items) { if (item.GetType() == typeof(Outlook.MailItem)) { Outlook.MailItem mi = (Outlook.MailItem)item; lbMail.Items.Add(mi.Subject); //------------------------------------------------------------------------- // mi.Subject is actually a folder name as it full path. // How to "open it" to get emails? // need loop here to modify .Subject of MailItem(s) in certain subfolders //------------------------------------------------------------------------- } } foreach (Outlook.Folder folder in theRootFolder.Folders) { RecurseThroughFolders(folder, depth + 1); } } 

I use listbox at this stage of work, and now the result is as follows. I want to "process" email messages in Projectnnnnnnn folders.

 \\Personal Folders \\Personal Folders\Deleted Items \\Personal Folders\Inbox \\Personal Folders\Inbox\MySubFolder \\Personal Folders\Inbox\MySubFolder\Project456212 \\Personal Folders\Inbox\MySubFolder\Project318188 \\Personal Folders\Inbox\Outbox \\Personal Folders\Inbox\SentItems 

EDIT:

I fixed this with a slight change to the loop above (i.e. removing the check that the current item is a mail item):

 foreach (Object item in theRootFolder.Items) { Outlook.MailItem mi = (Outlook.MailItem)item; string modifiedSubject = "Modifed Subject: " + mi.Subject; lbMail.Items.Add(modifiedSubject); mi.Subject = modifiedSubject; mi.Save(); // insert call webservice here to upload modified MailItem to new data store } 

Answer 1

While the above code may work, you are likely to encounter an unhandled InvalidCastException, since not all items in the root folder will be mail items (for example, meeting requests).
The following code worked for me:

 foreach (object item in items) { if (item is Outlook.MailItem) { ///The rest of your code } } 

Answer 2

// Iterate backwards due to .move below

 for (int i = theRootFolder.Items.Count; i > 0; i--) { Outlook.MailItem mi = (Outlook.MailItem)theRootFolder.Items[i]; if (mi != null) { if (!mi.Subject.StartsWith("M1")) { mi.Move(_TRIM_archiveFolder); } } }