you don't need to program at that low level, seeCOM Interop Part 1: C# Client Tutorial
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkCOMInteropPart1CClientTutorial.aspCOM Interop Part 2: C# Server Tutorial
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkCOMInteropPart2CServerTutorial.asp
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkCOMInteropPart1CClientTutorial.aspCOM Interop Part 2: C# Server Tutorial
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkCOMInteropPart2CServerTutorial.asp
.NET只是支持某种COM组件和.NET组件之间通信和转换的Bridge,.NET并不真的完全支持COM组件编写,而且象saucer说的那样,隐藏了很多底层细节。