A.2. Downloading the .NET Framework Software Development Kit

The .NET Framework is available as a free download from the Microsoft web site. The exact download URL changes from time to time, so the most dependable way to get to the download is to go to the MSDN home page:

http://msdn.microsoft.com

Near the top of the page, click the Downloads tab to go to the MSDN Download Center, from which you can find the necessary downloads. The .NET Framework download includes everything developers need to write, build, test, and deploy C# applications: documentation, samples, and command-line tools and compilers.

Among other things, the download comes with the following:

• A command-line C# compiler (csc.exe)

• The common language runtime (CLR)—the engine that runs compiled C# programs

• A wide variety of utility tools, including a runtime debugger

• Complete documentation for everything in the .NET Software Development Kit (SDK), including the contents of the .NET Framework Class Libraries

You must download two separate sets of software to get C# and .NET running on your machine:

• First, download and install the .NET Framework Redistributable package, which package contains the CLR and other .NET Framework components that are needed to run .NET Framework applications. It's best to download and install the latest version of the.NET Framework Redistributable package, but check the "Supported Operating Systems" information. You might have to go with an older version of the package if you are running an older operating system. You might also have to update your computer with one or more Service Packs in order to properly install and use the components.

• After the .NET Framework Redistributable package is installed on your machine, download and install the .NET Framework. Again, try to install the latest version, but make sure that your operating system is supported by the latest download. This download contains everything you will need to write, compile, test, and deploy C# applications, including documentation, libraries, compilers, and command-line tools.

Follow the instructions provided by Microsoft for installing both the Redistributable package and the .NET Framework on your particular system.