C# JSON 转换成 LIST对象，list对象为空值

我把JSON转换成LIST对象，但就是LIST里的数据为空，请高手指一下,代码如下：
JSON数据为：[{"xh":"0","xm":"AAA","xb":"男","csny":"1919-01-01"},{"xh":"1","xm":"AAA","xb":"男","csny":"1919-01-01"},{"xh":"2","xm":"AAA","xb":"男","csny":"1919-01-01"}] J