DataContractJsonSerializer returning nulls .Net4.0

这是我需要反序列化的json字符串：

[{"id":5236083584722820,"name":"IT_Projects","accessLevel":"EDITOR"},
{"id":2034305724639108,"name":"IT_Task","accessLevel":"EDITOR"},
{"id":2249810003683204,"name":"On-Hold","accessLevel":"EDITOR"}]

这是代码：

[DataContract]
public class SSCollection
{    
    [DataMember]
    public List<SSheets> sheetObjects { get; set; }
} 
[DataContract]
public class SSheets 
{
    [DataMember]
    public Int64 id { get; set; }
    [DataMember]
    public string name { get; set; }
    [DataMember]
    public string accessLevel { get; set;}
}
using (var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(json)))
        {
            memoryStream.Position = 0;
            var serializer = new DataContractJsonSerializer(typeof(SSCollection));
            SSCollection ss = (SSCollection)serializer.ReadObject(memoryStream);                 
            return ss;
        }

我不知道如何处理json字符串，它看起来是一个数组，但没有命名。我尝试过使用SSheets DataContract和使用SSCollection，两者都返回null，除非当我使用SSheet时，我得到id为0，字符串名称和accessLevel为null。任何帮助都将不胜感激。谢谢