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The multi-targeting feature of Visual Studio 2010 allows web developers to develop web applications targeting ASP.NET 2.0, 3.0, 3.5 and 4.0. Our earlier posts here and here describe some of the multi-targeting capabilities of Visual Studio 2010.
Targeting frameworks 2.0, 3.0 or 3.5 using VS 2010 requires 3.5 Sp1 to be installed
With VS 2010, only the latest 4.0 version of the .NET framework will be installed on your machine as part of the Visual Studio installation. For VS 2010 to be able to target any of the earlier frameworks 2.0, 3.0 or 3.5, the .NET Framework 3.5 Sp1 must be installed on the machine.
When 3.5 Sp1 is not present
If 3.5 Sp1 was not already present on your machine prior to installation of VS 2010, you will see the following behavior when you start VS 2010:
To then be able to target 2.0, 3.0 or 3.5 using VS 2010, you should install the 3.5 Sp1 framework from the installation page. To quickly navigate to the installation page, you can use the 'More Frameworks' link in figure 1 or select the option 'Take me to the Framework Download Web Site' in figure 3.
When 3.5 Sp1 is installed
Once 3.5 Sp1 is installed, then simply restart VS 2010 and the earlier frameworks such as 2.0, 3.0 and 3.5 will now light-up as available target frameworks.
Bala Chirtsabesan | SDET | Visual Studio Web Developer
So when beta 2 will be released?
Which versions of Sql Server Integration Services will we be able to target? Can I finally get rid of VS2005 if I need to edit SQL2005 SSIS packages?