LINQ in BizTalk?
Intriguing title, and I think it can be done. It might not be practical, not yet. We'll get there eventually. But for now...
There are ways to utilize many of the C# 3.0 features in 2.0, even extension methods, and there is even a LINQ library that allows you to do LINQ to objects in .NET 2.0. However these approaches still requires Visual Studio 2008 (or rather the C# 3.5 compiler), since they make use of Visual Studios multi-targeting features. And if you have to use Visual Studio 2008 there is really no point in not using .NET 3.5. But BizTalk doesn't work with VS.NET 2008 yet. At least not the Visual part. There should however not be anything stopping you from building for example pipeline components or functoids with Visual Studio 2008. The way I've understood it, it's "only" the designers and project templates that are missing. And since Visual Studio 2008 functions side-by-side with Visual Studio 2005, it's totally plausible to do one type of development in one tool and the other in another. Not very practical though. I'm guessing we have to wait quite awhile to get VS.NET 2008 support. Information about when this will be is scarce, about the only thing I've found is below.
From Paul Somers blog (Pauls blog seems to frequently use more resources than allowed and can at times not be viewed, so I am choosing to reproduce part of it here. The blogpost itself seems to be quoting someone else, but I couldn't say whom or what)
With the launch of Windows Server 2008, SQL Server 2008 and Visual Studio 2008 right around the corner, a number of you have asked when you will be able to take advantage of the new platforms with BizTalk Server. We are currently investigating various options to deliver updates prior to Oslo. As we have done historically, this would follow the RTM of Windows Server and SQL Server. This will give us time to do the final work and testing to ensure compatibility. Our intent is to provide an integrated release that supports the updated Tools (Visual Studio 2008), OS (Windows Server 2008) and DB (SQL Server 2008) as part of an infrastructure update.
To me this suggest availability at the earliest somewhere in Q4 2008, if we're lucky, since at the moment SQL 2008 is planned for Q3. This will probably happen through a SP1 for BizTalk Server 2006 and R2. And based on the above that release will be much larger then just tools, or even .NET 3.5, compliance.
With all that said, although I think LINQ and the new language features are cool, I can't really say it's something that I am really missing in BizTalk development. Being able to run BizTalk on Windows Server 2008 utilizing SQL Server 2008 excites me more then getting access to LINQ. Oh, and don't take this post as stating truths, it's just my 5 cents as it stands right now.
[Edit: For an example of using LINQ to XML in a helper class from an Orchestration, view my post here.]