C# Json格式转换成List集合

public List<User> JsonToList(string str)
{
str = "{"User":[{"Name":"Sony","Age":7},{"Name":"Samsumg","Age":14},{"Name":"LG","Age":21},{"Name":"Vizio","Age":34},{"Name":"Insignia","Age":24}]}";
JavaScriptSerializer json = new JavaScriptSerializer();
var list = json.DeserializeObject(str) as IDictionary<string,object>;
var groups =( from s in (IEnumerable<object>)list["User"]
let i = s as IDictionary<string, object>
where i != null
select new User()
{
Name = (string)i["Name"],
Age = (int)i["Age"]
}).ToList();
return groups;
}

public class User
{
public string Name { get; set; }
public int Age { get; set; }
}

要添加System.Web.Extensions.dll的引用