Converting VS2008 Solution to VS2010 Creates compile errors in ASP.NET 3.5 SP1

I am converting a large solution from Visual Studio 2008 to Visual Studio 2010. The conversion completes without errors. When I go to build the solution one particular section of the application throws error but it didn't when the solution was 2008.

Error 1 Could not load file or assembly 'System.Web.DataVisualization, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. C:\MyProject\Results\Result.ascx 3

And

C:\CMyProject\Results\Result.ascx(3): Build (web): Could not load file or assembly 'System.Web.DataVisualization, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

The dll is in the bin and it is not in the GAC开发者_如何学Go. The .refresh file is pointing to the correct location. And all sections in the Web.Config are there, if you need to see them let me know.

I have gone over the fixes I found online and nothing seems to help. I would really appreciate if someone could help me or point me in the right direction?

Thank You.

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Try to install Microsoft Chart Controls for Microsoft .NET Framework 3.5. You can find it on http://www.microsoft.com/downloads/details.aspx?FamilyID=130f7986-bf49-4fe5-9ca8-910ae6ea442c&DisplayLang=en

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That is the charting control, you probably need to get the latest that works with .net 4.0

Some information about it is at: http://msdn.microsoft.com/en-us/library/ee410579(VS.100).aspx