Microsoft has made Visual Studio 2010 and .NET 4 beta 2 available today to MSDN subscribers with general availability on Wednesday (10/21).

Download the beta from: http://msdn.microsoft.com/en-us/vstudio/dd582936.aspx

There are several new features available which you can read about at the following links:

Scott Guthrie has written several great posts detailing new features in Visual Studio 2010:
http://weblogs.asp.net/scottgu/archive/2009/08/25/vs-2010-and-net-4-series.aspx

What's new in ASP.NET 4.0 (Microsoft Whitepaper):
http://www.asp.net/learn/whitepapers/aspnet40/

Learning Resources for C# 4.0 and .NET 4.0:
http://bogdanbrinzarea.wordpress.com/2009/04/24/learning-net-40-new-features/

I was recently tasked with generating a string of averages based on a list of business objects.  The business object has a string property called VehicleName and a decimal property called StandardMpg.  The averages needed to be calculated per VehicleName, so this is to be what I group on.  This took me a few minutes to wrap my mind around, but once I got it, it seemed fairly simple. I thought it would be worth sharing with the rest of you:

string averages = string.Format("Avg: {0}",
    string.Join(" | ", gasMileageList
        .GroupBy(x => x.VehicleName)
        .Select(c => string.Format("{0} {1} MPG", c.Key, Math.Round(c.Average(x => x.StandardMpg), 1))).ToArray()));

The output will look something like: "Avg: bmw 21 MPG | kia 30 MPG"

Another option would be to dump the averages out to a list of objects, instead of a string.  To do this you can do:

Well I did it!  I got married on September 12 to my beautiful wife, Alejandra, in South Lake Tahoe.  I couldn't ask for a better girl (hell, she's a .NET developer, too!).