C#生成树形结构泛型类

C#生成树形结构泛型类，使用方法： ToTree<ShowMessageUpdatesTableTreeViewModel>.ToDo(models)

public class ToTree<T> where T : IToTreeModel
{
    public static List<T> ToDo(List<T> models)
    {
        var dtoMap = new Dictionary<int, T>();
        foreach (var item in models)
        {
            dtoMap.Add(item.Id, item);
        }
        List<T> result = new List<T>();
        foreach (var item in dtoMap.Values)
        {
            if (item.ParentId == )
            {
                result.Add(item);
            }
            else
            {
                if (dtoMap.ContainsKey(item.ParentId))
                {
                    dtoMap[item.ParentId].AddChilrden(item);
                }
            }
        }
        return result;
    }
}

实体类必须实现接口：

public interface IToTreeModel
{
    int Id { get; set; }
    int ParentId { get; set; }
    List<IToTreeModel> children { get; set; }
    void AddChilrden(IToTreeModel node);
}

实体类实例：

    public class ShowMessageUpdatesViewModel: IToTreeModel
    {
        public int Id { get; set; }
        public int ParentId { get; set; }
        public string Name { get; set; }
        public List<IToTreeModel> children { get; set; }
        public void AddChilrden(IToTreeModel node)
        {
            if (children == null)
                children = new List<IToTreeModel>();
            this.children.Add(node);
        }
    }