Microsoft .NET Framework 4.5 Developer Preview

The Microsoft .NET Framework 4.5 Developer Preview is a prerelease version of the .NET Framework, and should not be used in production scenarios. This software is an in-place update to the .NET Framework 4, and is designed to run side-by-side with the .NET Framework 3.5 and earlier versions. Learn More about how the .NET Framework 4.5 Developer Preview interacts with earlier versions. The .NET Framework 4.5 Developer Preview includes updates to the common language runtime (CLR) and the .NET Framework class library, innovations in the Visual Basic and C# languages, enhancements in data access and web server scenarios, and improvements in extensibility, performance, reliability, and security.