What technology was .NET implemented with?

Answer 1

No, it's not true.

The .Net runtime is written in C++, and most of the framework library is C#.

You can see a shared-source implementation here.

Answer 2

This has been discussed in this question:

http://stackoverflow.com/questions/2280639/is-net-all-com-underneath

Answer 3

You should probably read this post:

http://stackoverflow.com/questions/1083368/whats-the-early-history-of-the-net-framework

Answer 4

It's actually mostly C++, as mentioned by SLaks. But the Winforms controls, ah, now those have a lot of COM under the hood as many of the controls are merely wrappers or minor upgrades for prior MFC controls that used COM.