unit Unit3;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, ComCtrls, DB, ADODB, StdCtrls;

type

   PNodeInfo=^TNodeInfo;

   TNodeInfo=record

     ID:string;

     FullName:string;

     Url:string;

   end;

  TForm3 = class(TForm)

    ADOConnection1: TADOConnection;

    ADOQuery1: TADOQuery;

    TreeView1: TTreeView;

    Button1: TButton;

    procedure CreateChildTree(ParentNode: TTreeNode);

    procedure CreateViewTree(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure TreeView1DblClick(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form3: TForm3;

implementation

{$R *.dfm}

procedure TForm3.CreateChildTree(ParentNode: TTreeNode);

var

  Query:TADOQuery;

  ChildNode:TTreeNode; //孩子结点

  ChildNodeInfo:PNodeInfo; //孩子结点信息

begin

  Query:=TADOQuery.Create(nil);

  with Query do

  begin

    Connection:=ADOConnection1;

    SQL.Add('SELECT ID,FullName,Url FROM PInfo WHERE ParentID = '''+PNodeInfo(ParentNode.Data)^.ID+''''); //获取孩子结点信息

    Open;

    while not Eof do

    begin

      New(ChildNodeInfo);

      ChildNodeInfo^.ID:=FieldByName('ID').AsString;

      ChildNodeInfo^.FullName:=FieldByName('FullName').AsString;

      ChildNodeInfo^.Url:=FieldByName('Url').AsString;

      ChildNode:=TreeView1.Items.AddChildObject(ParentNode,(ChildNodeInfo^.FullName),ChildNodeInfo); //添加孩子结点，并关联孩子结点信息

      CreateChildTree(ChildNode); //进行递归

      Next;

    end;

    Close;

  end;

end;

procedure TForm3.CreateViewTree(Sender: TObject);

var

  BootNode:TTreeNode; //根结点

  BootNodeInfo:PNodeInfo; //根结点信息

begin

  with ADOQuery1 do

  begin

    SQL.Clear;

    SQL.Add('SELECT ID,FullName,Url FROM PInfo WHERE ParentID IS NULL'); //获取根结点信息

    Open;

    New(BootNodeInfo);

    BootNodeInfo^.ID:=FieldByName('ID').AsString;

    BootNodeInfo^.FullName:=FieldByName('FullName').AsString;

    BootNodeInfo^.Url:=FieldByName('Url').AsString;

    TreeView1.Items.Clear;

    BootNode:=TreeView1.Items.AddChildObject(nil,(BootNodeInfo^.FullName),BootNodeInfo); //添加根结点，并关联根结点信息

    Close;

  end;

  CreateChildTree(BootNode); //创建子树

  TreeView1.FullExpand; //展开所有树结点

end;

procedure TForm3.Button1Click(Sender: TObject);

begin

   CreateViewTree(Sender);

end;

procedure TForm3.TreeView1DblClick(Sender: TObject);

var

  TNode:TTreeNode;

  X,Y:Integer;

begin

  //获取双击的结点

  with TreeView1 do

  begin

    X:=ScreenToClient(Mouse.CursorPos).X;

    Y:=ScreenToClient(Mouse.CursorPos).Y;

    TNode:=GetNodeAt(X,Y);

  end;

  if (TNode<>nil) and (TNode=TreeView1.Selected) then

    ShowMessage(PNodeInfo(TNode.Data)^.Url); //显示双击结点的信息

end;

end.