The Windows Software Development Kit [SDK] is the SDK for
developing Windows applications, Windows SDK contains documentation for all
APIs of .Net Framework 3.0 [WinFx] interfaces, types, etc. found in the Windows
operating system. It also contains samples, tools and build environments. The
Windows SDK includes all the content you would previously have found in the
Platform SDK, Typically Unmanaged APIs, Samples and Tools.
So Windows SDK can be used as the basic guide to develop
applications for Windows Operating Systems by using .NET Framework 3.0 [WinFx].
You can download the Windows SDK by following the below URL:
[INSTALLATION OF WINDOWS SDK IS NOT MANDATORY TO WORK
WITH THE WinFx]
Windows SDK for .NET Framework 3.0