My favorite library to serialize/deserialize .NET objects to and from JSON is the NewtonSoft JSON library. This library is fast and does the right thing the first time you use it in your application. When Microsoft started to use this library in ASP.NET Web API, I made a little virtual jump of joy in my mind. It means we have a defacto-standard library instead of something Microsoft came up with for themselves. Not that I mind Microsoft building their own thing, but some things you shouldn't do yourself when someone else has a better solution.
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