System.Web.Script.Serialization.JavaScriptSerializer

System.Web.Script.Serialization.JavaScriptSerializer
This was added in .NET 3.5
You need to add the System.Web.Extensions namespace

System.Web.Script.Serialization.JavaScriptSerializer oSerializer; 
oSerializer = new System.Web.Script.Serialization.JavaScriptSerializer(); 
oSerializer.Deserialize<dynamic>(value); 

oSerializer.Serialize(oMyObject);