关于地址添加 子窗体向父窗体传值 树的使用详细

namespace ItcastSIMS
{
    public partial class FrmArea : Form
    {
        public FrmArea()
        {
            InitializeComponent();
        }
        AreaBLL bll = new AreaBLL();
        List<Areas> list;//数据库地址信息
        private void FrmArea_Load(object sender, EventArgs e)
        {
            list = bll.GetAllAreas();
            tvAreas.Nodes.Clear();//默认节点清空
            CreateParent();
        }

        private void CreateParent()
        {
            TreeNode parent = new TreeNode();
            parent.Text = "全国";
            parent.Tag = 0;
            tvAreas.Nodes.Add(parent);//添加父节点

            //添加子节点
            CreateChild(parent);


            //展开
            //tvAreas.ExpandAll();
            parent.Expand();
        }
        
        private void CreateChild(TreeNode parent)
        {
            //父节点的id
            int pid = Convert.ToInt32(parent.Tag);

            foreach (Areas a in list)
            {
                if (a.APid == pid)
                {
                    TreeNode tn = new TreeNode();
                    tn.Text = a.AName;
                    tn.Tag = a.AID;
                    parent.Nodes.Add(tn);

                    //递归调用，加载子节点
                    CreateChild(tn);
                }
            }
        }

        private void btnSure_Click(object sender, EventArgs e)
        {
            //获取选中的节点
            GetTNText(tvAreas.SelectedNode);
            txt += tvAreas.SelectedNode.Text;
            DialogResult = System.Windows.Forms.DialogResult.OK;
        }
        public string txt = "";
        /// <summary>
        /// 获取选中节点的父节点的内容
        /// </summary>
        /// <param name="tn"></param>
        /// <returns></returns>
        void GetTNText(TreeNode tn)
        {
            if (tn.Parent != null)
            {
                GetTNText(tn.Parent);
                txt += tn.Parent.Text + "-";
            }
        }
    }

}

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 //选择地区
        private void btnChooseArea_Click(object sender, EventArgs e)
        {
            FrmArea frm = new FrmArea();

            if (frm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                txtArea.Text = frm.txt;
            }
        }