Outlook Developer: Outlook Object Model API, IRM, Do not forward option

With Outlook Object Model (OOM) API, now you can access the Outlook mail item and its permission property programmatically.

You can set the Permission property - using that you can set or returns an OlPermission constant that determines the permissions the recipients will have on the e-mail item.

C++

 public:
 property Microsoft::Office::Interop::Outlook::OlPermission Permission { 

  Microsoft::Office::Interop::Outlook::OlPermission get(); 

 void set(Microsoft::Office::Interop::Outlook::OlPermission value); };

If you look at the related documentation you will see that you need to programmatically turn on the "Do Not Forward" option, you will want to set the value of that property to OlPermission.olDoNotForward. Also there is another IRM-related property (PermissionTemplateGuid), but it appears that you can leave this as an empty string since you are using a built-in "permission".

The Permission property should be synchronized with the PermissionTemplateGuid property to accurately reflect the permission status of the SharingItem. Setting the PermissionTemplateGuid property to a valid GUID should also incur setting the Permission property to olPermissionTemplate. When no Information Rights Management (IRM) has been set up (in which case the Permission property is olUnrestricted), or the restriction is not to forward the SharingItem (in which case the Permission property is olDoNotForward), the value of the PermissionTemplateGuid property should be an empty string.

Hope this helps.