Read MS Exchange email in C#

It's a mess. MAPI or CDO via a .NET interop DLL is officially unsupported by Microsoft--it will appear to work fine, but there are problems with memory leaks due to their differing memory models. You could use CDOEX, but that only works on the Exchange server itself, not remotely; useless. You could interop with Outlook, but now you've just made a dependency on Outlook; overkill. Finally, you could use Exchange 2003's WebDAV support, but WebDAV is complicated, .NET has poor built-in support for it, and (to add insult to injury) Exchange 2007 nearly completely drops WebDAV support.

What's a guy to do? I ended up using AfterLogic's IMAP component to communicate with my Exchange 2003 server via IMAP, and this ended up working very well. (I normally seek out free or open-source libraries, but I found all of the .NET ones wanting--especially when it comes to some of the quirks of 2003's IMAP implementation--and this one was cheap enough and worked on the first try. I know there are others out there.)

If your organization is on Exchange 2007, however, you're in luck. Exchange 2007 comes with a SOAP-based Web service interface that finally provides a unified, language-independent way of interacting with the Exchange server. If you can make 2007+ a requirement, this is definitely the way to go. (Sadly for me, my company has a "but 2003 isn't broken" policy.)

If you need to bridge both Exchange 2003 and 2007, IMAP or POP3 is definitely the way to go.

Um,

I might be a bit too late here but isn't this kinda the point to EWS ?

https://msdn.microsoft.com/en-us/library/dd633710(EXCHG.80).aspx

Takes about 6 lines of code to get the mail from a mailbox:

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);

//service.Credentials = new NetworkCredential( "{Active Directory ID}", "{Password}", "{Domain Name}" );

service.AutodiscoverUrl( "[email protected]" );

FindItemsResults<Item> findResults = service.FindItems(
   WellKnownFolderName.Inbox,
   new ItemView( 10 ) 
);

foreach ( Item item in findResults.Items )
{
   Console.WriteLine( item.Subject );
}

1. The currently preferred (Exchange 2013 and 2016) API is EWS. It is purely HTTP based and can be accessed from any language, but there are .Net and Java specific libraries.

   You can use EWSEditor to play with the API.

2. Extended MAPI. This is the native API used by Outlook. It ends up using the MSEMS Exchange MAPI provider, which can talk to Exchange using RPC (Exchange 2013 no longer supports it) or RPC-over-HTTP (Exchange 2007 or newer) or MAPI-over-HTTP (Exchange 2013 and newer).

   The API itself can only be accessed from unmanaged C++ or Delphi. You can also use Redemption (any language) - its RDO family of objects is an Extended MAPI wrapper. To use Extended MAPI, you need to install either Outlook or the standalone (Exchange) version of MAPI (on extended support, and it does not support Unicode PST and MSG files and cannot access Exchange 2016). Extended MAPI can be used in a service.

   You can play with the API using OutlookSpy or MFCMAPI.

3. Outlook Object Model - not Exchange specific, but it allows access to all data available in Outlook on the machine where the code runs. Cannot be used in a service.

4. Exchange Active Sync. Microsoft no longer invests any significant resources into this protocol.

5. Outlook used to install CDO 1.21 library (it wraps Extended MAPI), but it had been deprecated by Microsoft and no longer receives any updates.

6. There used to be a third-party .Net MAPI wrapper called MAPI33, but it is no longer being developed or supported.

7. WebDAV - deprecated.

8. Collaborative Data Objects for Exchange (CDOEX) - deprecated.

9. Exchange OLE DB Provider (EXOLEDB) - deprecated.