树实体
public class Combotree
{
public string id { get; set; }
public string text { get; set; }
public string state { get; set; }
public List<Combotree> children { get; set; }
}
只需要在初始化数据的时候给 state 设置为 closed
注意:不要在最后一级节点设置该字段为 closed