这个简单的树,如何显示出来?

Question

请问,如何将下方查询出数据结构 显示成树形?就是如果一个节点有子类,就可点击+号扩展看到.....(可能是无限的子类,最基础的父类ID已定为0)高人帮看看,可否提供示例代码?谢了...
自动编号 部门名   父ID
-----------------------------
33 电脑部 37
34 行政部 36
35 工程部 38
36 生产部 39
37 货仓部 38
38 深圳公司 0
39 上海公司 0
40 北京公司 0
...

Answer 1

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, StdCtrls, ComCtrls;type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    Button1: TButton;
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;type
  TRelateInfo = record
        id: integer;
        pid: integer;
end;
type PRelateInfo = ^TRelateInfo;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
var
        mTn: TTreeNode;
        mPrt: PRelateInfo;
        i,j: integer;
begin
        AdoQuery1.Active := False;
        AdoQuery1.SQL.Text := 'SELECT * FROM test4 ORDER BY pid';
        AdoQuery1.Open;
        TreeView1.Items.Clear;
        //添加全部节点，暂无隶属关系
        while not AdoQuery1.Eof do
        begin
                mTn := TreeView1.Items.AddChild(nil,AdoQuery1.FieldValues['dname']);
                new(mPrt);
                mPrt^.id := AdoQuery1.FieldValues['id'];
                mPrt^.pid := AdoQuery1.FieldValues['pid'];
                mTn.Data := mPrt;
                AdoQuery1.Next;
        end;        //遍历全部节点，修改隶属关系
        i:=0;
        while i<TreeView1.Items.Count do
        begin
                if PRelateInfo(TreeView1.Items.Item[i].Data)^.pid = 0 then
                begin
                        Inc(i);
                        Continue;
                end
                else
                begin
                        j:=0;
                        while j<TreeView1.Items.Count do
                        begin
                                if j=i then
                                begin
                                        Inc(j);
                                        Continue;
                                end;
                                if PRelateInfo(TreeView1.Items.Item[j].Data)^.id = PRelateInfo(TreeView1.Items.Item[i].Data)^.pid then
                                begin
                                        TreeView1.Items.Item[i].MoveTo(TreeView1.Items.Item[j],naAddChild);
                                        break;
                                end;
                                Inc(j);
                        end;
                        if j=TreeView1.Items.Count then
                                ShowMessage('非法数据：'+TreeView1.Items.Item[i].Text);
                        Inc(i);
                end;
        end;
        //清空隶属关系变量，回收内存
        //如果后续程序需要利用该关系变量，可在from的onDestroy事件中释放
        for i:=0 to TreeView1.Items.Count -1 do
        begin
                mTn := TreeView1.Items.Item[i];
                mPrt := mTn.Data;
                Dispose(mPrt);
                mTn.Data := nil;
        end;
end;end.

Answer 2

DBTreeView 可以搞定
keyID=自动编号   displayfield=部门名   ParentID=父ID