Find out by taking a look at the source code of the .NET Framework that, as Scott Guthrie announced today, is now available for debugger access from within Visual Studio 2008.
For now, the libraries that are available are:
- .NET Base Class Libraries (including System, System.CodeDom, System.Collections, System.ComponentModel, System.Diagnostics, System.Drawing, System.Globalization, System.IO, System.Net, System.Reflection, System.Runtime, System.Security, System.Text, System.Threading, etc).
- ASP.NET (System.Web, System.Web.Extensions)
- Windows Forms (System.Windows.Forms)
- Windows Presentation Foundation (System.Windows)
- ADO.NET and XML (System.Data and System.Xml)
They are released under a Reference License that basically lets you take a look at the code, but you cannot reuse it for your own projects. You still get access to the full source, including comments, which will hopefully give you a better understanding on how the Framework works. To learn how to configure Visual Studio to download the Framework’s source, that a look at Shawn Burke’s tutorial.
Reading other people’s code is an excellent way of becoming a better programmer, as has been discussed by people such as Scott Hanselman. Reading the .NET Framework’s code is one way to do it, but don’t forget that there’s plenty of code lying around on the Internet; some of it is even open source. Sites like Codeplex or Sourceforge are great places to start.