CDO and .NET

One thing to watch for with CDO is that certain versions of the CDO library are not supported in a .NET environment. For example, as of this writing, CDO 1.21 is not supported by Microsoft if you use it via COM interop from Visual Studio .NET. CDO for Exchange, CDO for Exchange Management, Web Distributed Authoring and Versioning (WebDAV), Windows Management Instrumentation (WMI), Collaboration Data Objects (CDO) for Windows, and the OLEDB provider for Exchange are supported in .NET. You should check Microsoft Knowledge Base article 813349 regularly because support policies can change without notice. With that said, I've worked extensively with CDO 1.21 using .NET and have samples that use .NET in this book. In my testing, CDO 1.21 seems to work fine with just a few little quirks in the .NET environment. However, you should judge for yourself whether using .NET and CDO 1.21 will meet the needs of your project and whether its lack of official support is acceptable. You can always go back to Visual Studio 6.0 and not use .NET if you find it unacceptable.