C# -使用List.Add时Class.models.modelname.list.get返回null

public class ClassName
{
    public List<AnotherClass> models { get; set; }

    public ClassName()
    {
        models = new List<AnotherClass>();
    }
}

public class ClassName
{
    private List<AnotherClass> _models;

    public List<AnotherClass> models
    {
        get
        {
            if (_models == null)
            {
                _models = new List<AnotherClass>();
            }
            return _models;
        }
        set { _models = value; }
    }
}