public class Menus

{

    //菜单Id

    public int Id { get; set; }

    //菜单名

    public string MenuName { get; set; }

    //父节点Id

    public int ParentId { get; set; }

}

private static List<Menus> menus;

private void button1_Click(object sender, EventArgs e)

{

    menus = new List<Menus>();

    menus.Add(new Menus { Id = 1, MenuName = "基础设置", ParentId = 0 });

    menus.Add(new Menus { Id = 2, MenuName = "采购管理", ParentId = 0 });

    menus.Add(new Menus { Id = 3, MenuName = "系统设置", ParentId = 1 });

    menus.Add(new Menus { Id = 4, MenuName = "用户管理", ParentId = 1 });

    menus.Add(new Menus { Id = 5, MenuName = "采购订单", ParentId = 2 });

    menus.Add(new Menus { Id = 6, MenuName = "采购入库", ParentId = 2 });

    menus.Add(new Menus { Id = 7, MenuName = "用户", ParentId = 4 });

    menus.Add(new Menus { Id = 8, MenuName = "采购退货", ParentId = 2 });

    menus.Add(new Menus { Id = 9, MenuName = "用户组", ParentId = 4 });

    menus.Add(new Menus { Id = 10, MenuName = "权限管理", ParentId = 4 });

    //首先查出顶级菜单，循环添加

    IEnumerable<Menus> menu = from m in menus where m.ParentId == 0 orderby m.ParentId select m;

    foreach (var item in menu)

    {

        TreeNode node = new TreeNode();

        node.Tag = item;

        node.Text = item.MenuName;

        treeView1.Nodes.Add(node);

        //将当前节点作为参数传入子节点

        AddChildMenu(node);

    }

}

private void AddChildMenu(TreeNode node)

{

    Menus menu = new Menus();

    menu = (Menus)node.Tag;   //将父节点转为Model

    //查出当前子节点中所有同父节点Id一样的数据

    IEnumerable<Menus> childMenu = from m in menus where m.ParentId == menu.Id orderby m.Id select m;

    foreach (var item in childMenu)

    {

        TreeNode childNode = new TreeNode();

        childNode.Tag = item;

        childNode.Text = item.MenuName;

        node.Nodes.Add(childNode);  //添加子节点

        AddChildMenu(childNode);    //递归调用自己，直到父节点添加所有子节点结束

    }

}