Visual Studio 2010 Cannot Use System.Threading.Tasks;

I am trying to execute some processes in parallel. and it is my first time doing that, upon trying : using System.Threading.Tasks; Tas开发者_如何学Pythonks will be underlined in red saying :

The Type or namespace name "Tasks" does not exist in the namespace System.Threading(are you missing an assembly reference?)

how do i resolve that!?

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Does your project target .NET 3.5 or lower, perhaps? System.Threading.Tasks was introduced in .NET 4 - just using Visual Studio 2010 isn't enough; you need to target the appropriate framework. (Fortunately it is in the .NET 4 client profile, which is often a little "gotcha" for some other types.)

Likewise Silverlight hasn't yet got the TPL, although IIRC it's coming in Silverlight 5.

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Make sure that you are targeting .NET 4.0 in the properties of your project. TPL is not available in previous versions of .NET.

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You have to change the Target Framework to 4.0 of your project.

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Have you tried to add it by right clicking on add reference button in visual Studio?