Yes, the current version of .NET is .NET 3.5. It contains new features, but the most notable new feature is the release of LINQ, Language INtegrated Query.
First, let's talk about CLR in .NET 3.5
But before I delve more deep, let's see the fact that there's no new CLR for this release (3.5) since .NET 2.0. Again, Daniel Moth has brought us quite deep explanation about this. But this is quite a relieve, since the incompatibilities of .NET 1.x and .NET 2.0. I remember when I was finishing ASP.NET 1.1 project, my client's web hosting quietly changed their .NET version to 2.0. And then ASPX pages stopped working, since almost all of them displayed errors and exceptions. (I won't share the name of my client's web host, but email or message me in private if you want to).
I'm happy that there's no new CLR at this moment of 3.5. There are (yes, even until now, not were) some irrelevant arguments about whether there's a new CLR or not. If you find news about new LINQ and new CLR, and if there's somebody thinks new that new language keywords == new CLR, you're dead wrong! LINQ and .NET 3.5 don't bring new CLR. These new language keywords and hence, constructs, are not bringing new CLR. These new keywords of LINQ in C# 3.0 and VB 9 are just language features. Your new CLR of 3.5 still run under .NET 2.0, unless you're using newer class libraries of .NET 3.5.
Can I have the illustration about this?
On many occasions, Microsoft's bloggers often mention red bits, green bits, and some additional features in .NET 3.5. Somasegar, the VP of Dev Division at Microsoft, also discussed what these color bits mean.
Hmm... looks like more and more headache concerning new technologies? Fear not, there are numerous resources of .NET 3.5 for us. From that simple Venn diagram above, it's clear that .NET 3.5 is also .NET 2.0.
So, green bits are what we have now, the .NET 3.5!
Basically, .NET 3.5 in long math equation is:
.NET 3.5 = .NET 2.0 SP1 + .NET 3.0 SP1 + new features
What are the new features, really?
In short, these are:
- Lambda Expression in C# 3.0 and VB 9
- WPF 2D on 3D support
- Integration of MS Ajax Extension into base .NET 3.5 assembly.
- Addins API
Unfortunately, there's no single file for .NET 3.5 redistributable runtime to download. Even .NET 3.5 SDK, is not available in its full form, unlike the .NET 3.0 SDK that ships as part of Windows SDK 6.0.
So, there's no standalone .NET 3.0 SDK to download. Another sad thing is, there's no standalone .NET 3.5 SDK to download at this time. .NET 3.5 SDK will be included in release of Windows 2008 SDK, which is about 1.3 GB in size!
Try to download Windows 6.0 SDK? It's whopping 1.2GB in size! Unless you have broadband connection at least DSL, you should wait for VS 2008 Standard Edition or Professional Edition to be sold worldwide, or you can get them if you're MSDN Premium subscriber.
More on LINQ and other new features? Stay tuned!