Newtonsoft.Json序列化踩坑：IEnumerable

public class Test : IEnumerable
{
    public string str1 = "字段字符串";
    public string str2 { get; set; } = "属性字符串";

    private string s="私有字段";
    public string S { get { return s; } set { s = value; } }
    [JsonProperty]
    List<TestNode> lstDrillTools = new List<TestNode>();
    public Test()
    {
        int index = 0;
        lstDrillTools.Add(new TestNode() { str1= (index++).ToString()});
        lstDrillTools.Add(new TestNode() { str1 = (index++).ToString() });
        lstDrillTools.Add(new TestNode() { str1 = (index++).ToString() });
        lstDrillTools.Add(new TestNode() { str1 = (index++).ToString() });
        lstDrillTools.Add(new TestNode() { str1 = (index++).ToString() });
    }


    [OnDeserializing()]
    internal void OnDeserializingMethod(StreamingContext context)
    {
        lstDrillTools.Clear();//反序列化前 清空
    }

    public TestNode this[int index]
    {
        get
        {
            return lstDrillTools[index];
        }
        set { lstDrillTools[index] = value; }
    }

    /// <summary>
    /// 遍历钻具组合
    /// </summary>
    /// <returns>返回钻具组合的枚举器</returns>
    public IEnumerator GetEnumerator()
    {
        if (lstDrillTools != null)
        {
            for (int i = 0; i < lstDrillTools.Count; i++)
            {
                yield return lstDrillTools[i];
            }
        }
    }
}

public class TestNode
{
    public string str1 = "字段字符串";
    public string str2 { get; set; } = "属性字符串";

    public bool isBool=false;
}