如何确定Office365上的退回电子邮件消息？

Question

I'm using Exchange web service to read email from Office365. The C# program works fine. I can get EmailMessage in Inbox, and get their subject and message body, etc. However, I could not figure out the way to check whether the message is a bounce back message or not.

Do I have to parse the message body to see whether there are some special sentence, ie. Mail Delivery Failure? If so, is it possible different email servers bounce back emails with different words? ie some use 'Mail Delivery Failure', some use 'Mail Delivery Not Succeeded'? (just an example, I do not know whether this is true)

Or, the message object has an attribute that can be used for this purpose?

Thanks

*** Just found that the exchange webservice can not see 'Bounce back' messages in INBOX. I'm using below code, all messages can be 'seen' except Bounce Back ones. Do I miss anything to filter te bounce back messages? They are actually in INBOX, unread, and I can see it from Office365 page.

private static void ProcessEmailMessages(SearchFolder searchFolder, Folder folderHistory, Folder folderBounceBack)
{
    if (searchFolder == null)
    {
        return;
    }

    const Int32 pageSize = 50;
    ItemView itemView = new ItemView(pageSize);

    PropertySet itempropertyset = new PropertySet(BasePropertySet.FirstClassProperties);
    itempropertyset.RequestedBodyType = BodyType.Text;
    itemView.PropertySet = itempropertyset;

    PropertySet propertySet = new PropertySet(BasePropertySet.IdOnly, FolderSchema.DisplayName);
    folderHistory.Load(propertySet);
    folderBounceBack.Load(propertySet);

    FindItemsResults<Item> findResults = null;
    do
    {
        findResults = searchFolder.FindItems(itemView);
        foreach (Item item in findResults.Items)
        {
            if (item is EmailMessage)
            {
                // load body text
                item.Load(itempropertyset);

                EmailMessage email = item as EmailMessage;
                //email.Move(folder.Id);

                // check email subject to find the bounced emails
                bool subjectContains = Regex.IsMatch(email.Subject, "Mail Delivery Failure", RegexOptions.IgnoreCase);
                bool bodyContains = Regex.IsMatch(email.Subject, "Delivery", RegexOptions.IgnoreCase);
                if (subjectContains || bodyContains)
                {
                    email.Move(folderBounceBack.Id);
                    Console.WriteLine("Move the Bounced email: {0}", email.Subject);

                    ShowMessageInfo(email);
                }
                else
                {
                    email.Move(folderHistory.Id);
                    Console.WriteLine(">>> Keep the email: {0}", email.Subject);
                }
            }
        }

        itemView.Offset += pageSize;
    } while (findResults.MoreAvailable);
}

Answer 1

Check the ItemClass attribute. Messages like that should have a class that contains "REPORT" in it.

Answer 2

I use EWS in an O365 environment to help process bounce backs and use the following code to just get the NDRs from a users' inbox.

var sf = new SearchFilter.IsEqualTo(ItemSchema.ItemClass, "REPORT.IPM.Note.NDR");
var SearchFilter searchFilter = new SearchFilter.SearchFilterCollection(LogicalOperator.And, sf);
var view = new ItemView(1000) {PropertySet = new PropertySet(BasePropertySet.IdOnly)};
var findResults = service.FindItems(WellKnownFolderName.Inbox, searchFilter, view);

Hope it helps.