Support policy for Microsoft Exchange APIs with the .NET Framework applications

This article outlines the support policy for using various Exchange application programming interfaces in a Microsoft .NET Framework application. This article applies to all versions and service packs of both Microsoft Exchange Server 5.5 and Microsoft Exchange 2000 Server.

Microsoft is committed to providing the ability to programmatically access Exchange 2000 Server by using the latest available .NET technologies. If you build a .NET Framework application, the supported options for accessing Exchange data are:

• WWW Distributed Authoring and Versioning (WebDAV) through HTTP requests and responses.
• Collaboration Data Objects (CDO) for Exchange 2000 Server (CDOEX) and Exchange OLE DB provider (ExOLEDB) through an interop assembly.
• Windows Management Instrumentation (WMI).
• Collaboration Data Objects for Exchange Management (CDOEXM).

If the .NET application assemblies reside directly on the Exchange server, Microsoft recommends building the application by using CDOEX and ExOLEDB. If the .NET application assemblies do not reside directly on the Exchange Server, Microsoft recommends using WebDAV.

For .NET Framework applications that send mail without using Exchange Server as the transport, Microsoft CDO for Windows 2000 (CDOSYS) can be used through an interop assembly. However, Microsoft recommends using System.Web.Mail. System.Web.Mail is a managed wrapper to CDOSYS that enables you to construct and send messages by using the CDOSYS message component. The mail message is delivered either through the SMTP mail service that is built into Microsoft Windows 2000 or through an arbitrary SMTP server.

CDO 1.2x and MAPI are not supported in a .NET Framework environment. For CDO 1.2x and MAPI type functionality, use one of the supported access methods mentioned in the "Summary" section. For .NET Framework applications that must send mail without using Exchange Server as the transport, System.Web.Mail is a good option. However, Microsoft Collaboration CDOSYS can also be used through an interop assembly.

CDO 1.2x and MAPI are not supported in a .NET Framework environment.

MORE INFORMATION

For more information, visit the following MSDN Web sites:

.NET Interop: Get Ready for Microsoft .NET by Using Wrappers to Interact with COM-based Applications
http://msdn.microsoft.com/msdnmag/issues/01/08/interop/

Introduction to COM Interop
http://msdn2.microsoft.com/en-us/library/kew41ycz(vs.71).aspx

COM Interop Sample: .NET Client and COM Server
http://msdn2.microsoft.com/en-us/library/367d22wa(vs.71).aspx

Advanced COM Interop
http://msdn2.microsoft.com/en-us/library/bd9cdfyx(vs.71).aspx

Handling COM Interop Exceptions
http://msdn2.microsoft.com/en-us/library/awy7adbx(vs.71).aspx