Ultimately, the C# will end up calling into IE8's COM functions. There's a framework called Spicie that makes this easier, and some other examples here: http://www.enhanceie.com/ie/dev.asp
Generally, it's a bad idea to write browser extensions in .NET because there's a severe performance impact, and there's the possibility of runtime collisions because only one version of .NET can be loaded into a process currently; if two addons want to use conflicting .NET versions, one will fail.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…