How to change target of Asp.net mvc Project in Visual Web Developer Express

I want to use DataContractJso开发者_高级运维nSerializ class inside my Asp.net MVC Application. To be able to use it I found out that Im supposed to target a different the .NET 4.0 Framework.

But how can I change the target?

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Right click on the project, select 'Properties'. Under the 'Application' tab from the 'Target Framework' drop down, select '.NET Framework 4'