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c#outlookvstooutlook-addinoffice-addins

How to access header of mail in Outlook 2019 using VSTO?

In order to read the header a mail item in Outlook, I found the following solution for Outlook 2010 but it does not work with Outlook 2019 (and probably also not with Outlook 365).

var mailItem = item as MailItem;
if (mailItem != null)
{
    var header = mailItem.PropertyAccessor.GetProperty("http://schemas.microsoft.com/mapi/proptag/0x007D001E/");
...

Unfortunately I receive this error message:

System.ArgumentException: 'The property "http://schemas.microsoft.com/mapi/proptag/0x007D001E/" cannot be parsed or has an invalid format.'

So, how to read the header of an e-mail using C# and VSTO? What is considered to be best practice?

Solution

  • The DASL name is invalid - you have an extra trailing "/". Use "http://schemas.microsoft.com/mapi/proptag/0x007D001E".

    Be prepared to handle "not found" errors - no MAPI property is guaranteed to be present.

    If you want to see DASL property names for existing properties, take a look at a message with that property set with OutlookSpy (I am its author) - click IMessage button, select the property, copy the value of the DASL edit box.