In the comments of Scott Hanselman's blog posts on why VB developers don't switch/migrate/convert to VB.NET, someone replied with the following:
So what application has Microsoft written totally in .NET that is worth a [expletive]? Visual Studio - NO, Office - NO, Notepad - NO, Calc - NO. Why haven't they? .....
Here's my response. While the .NET Framework hasn't been around for a long period of time (shiping in February 2002), there is quite a lot of work being done by different teams to use the .NET Framework across Microsoft's product line. Below is a quick list of just some of the ways we're using managed code in products that ship today and how we plan to use managed code in the future.
OfficeWhile Office is a little behind in adopting the .NET Framework, you'll still find the .NET Framework in use, athough probably not as much as you would probably want. Then again, Office is also expanding itself from being stand alone applications to a fully integrated set of tools for collaboration as witnessed with the Microsoft Office System, and our server products with Web front ends pretty much all use ASP.NET.
Windows Server System
Microsoft Web Properties using the .NET Framework
Microsoft Internal applications using the .NET Framework
Does this mean Microsoft is only developing in managed code? No, definitely not. I would say the #1 language in use at Microsoft is C/C++. We also invest heavily in C++ and help support developers who need the power and performance C++ offers. We also have, in my opinion, the best C++ compiler of any platform.
And we're just getting started...