CODEWITHSUNDEEP
c#.netexchange-serverexchangewebservices
Nan Zhou
Nan Zhou

Reputation: 21

How to get the MessageId from all exchange items

Hello I recently got into development around EWS. One of the issue came up to me is that a client ask me to import emails into database and he wants to detect the duplicate based on InternetMessageID this way he doesn't have to import the duplicate emails and my code came up to this point.

 private static string GetInternetMessageID(Microsoft.Exchange.WebServices.Data.Item email)
{
EmailMessage emailMsg = email as EmailMessage;
string returnId = string.Empty;
if ((emailMsg != null)) {
    try {
        emailMsg.Load();
        //loads additional info, without calling this ToRecipients (and more) is empty
    } catch (ArgumentException ex) {
        //retry
        email.Load();
    }
    returnId = emailMsg.InternetMessageId;
} else {
    //what to do?
}
return returnId;

}

I can handle regular emails, but for special exchange objects such as contact, Calendar, Posts etc it does not work because it could not cast it to an EmailMessage object.

And I know you can extract the internetMessageId from those objects. Because the client used to have another software that extract this ID for them, maybe the property is not called internetMessageID, I think I probally have to extract it from the internetMessageHeader. However when ever I try to get it from the item object it just throws me an error. How do I get the internet messageID from these "Special" exchange items?

PS i am aware of item.id.UniqueID however that is not what I want as this id changes if I move items from folder to another folder in exchange

Upvotes: 2

Views: 1589

Answers (1)

Glen Scales
Glen Scales

Reputation: 22032

Only objects that have been sent via the Transport service will have an InternetMessageId so things like Contacts and Tasks because they aren't messages and have never been routed via the Transport service will never have an Internet MessageId. You probably want to look at using a few properties to do this InternetMessageId can be useful for messages PidTagSearchKey https://msdn.microsoft.com/en-us/library/office/cc815908.aspx is one that can be used (if you good this there are various examples of using this property).

If your going to use it in Code don't use the method your using to load the property on each item this is very inefficient as it will make a separate call for each object. Because these I'd's are under 256 Kb just retrieve then when using FindItems. eg

        ExtendedPropertyDefinition PidTagSearchKey = new ExtendedPropertyDefinition(0x300B, MapiPropertyType.Binary);
        ExtendedPropertyDefinition PidTagInternetMessageId = new ExtendedPropertyDefinition(0x1035, MapiPropertyType.String);
        PropertySet psPropSet = new PropertySet(BasePropertySet.IdOnly);
        psPropSet.Add(PidTagSearchKey);
        psPropSet.Add(PidTagInternetMessageId);
        ItemView ItemVeiwSet = new ItemView(1000);
        ItemVeiwSet.PropertySet = psPropSet;
        FindItemsResults<Item> fiRess = null;
        do
        {
            fiRess = service.FindItems(WellKnownFolderName.Inbox, ItemVeiwSet);
            foreach (Item itItem in fiRess)
            {
                Object SearchKeyVal = null;
                if (itItem.TryGetProperty(PidTagSearchKey, out SearchKeyVal))                                   
                {
                    Console.WriteLine(BitConverter.ToString((Byte[])SearchKeyVal));
                }
                Object InternetMessageIdVal = null;
                if (itItem.TryGetProperty(PidTagInternetMessageId, out InternetMessageIdVal))                                   
                {
                    Console.WriteLine(InternetMessageIdVal);
                }
            }
            ItemVeiwSet.Offset += fiRess.Items.Count;
        } while (fiRess.MoreAvailable);

If you need larger properties like the Body using the LoadPropertiesForItems Method https://blogs.msdn.microsoft.com/exchangedev/2010/03/16/loading-properties-for-multiple-items-with-one-call-to-exchange-web-services/

Upvotes: 1

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