tree.pas

《delphi数据库设计与实例开发》随书光盘

unit tree;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, DBTables, StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    Label1: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Label6: TLabel;
    Edit1: TEdit;
    Query1: TQuery;
    Query2: TQuery;
    Label2: TLabel;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    procedure FormCreate(Sender: TObject);
    procedure TreeView1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  node1,node2:TTreeNode;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
 Query1.DatabaseName:='DBDEMOS';
 Query2.DatabaseName:='DBDEMOS';
 with Query1 do
  begin
  Close;
  SQL.Clear;
  SQL.Add('select * from vendors');
  Open;
  end;
 While not Query1.eof do //遍历Query1
 begin
  node2:=TreeView1.Items.add(node1,Query1.FieldByName('VendorName').AsString);//增加树节点
  With Query2 do
  {查找出表parts的VendorNo字段内容和表vendors的VendorNo当前字段内容相同的所有记录}
  begin
   Close;
   SQL.clear;
   SQL.add('select * from parts where VendorNo=:a');
   Parambyname('a').AsInteger:=Query1.FieldByName('VendorNo').AsInteger;
   Open;
  end;
 Query2.first;
 While not Query2.eof do //遍历Query2
 begin
  Treeview1.items.addChildFirst(node2,Query2.fieldbyname('Description').AsString);//添加子节点
 Query2.next; //记录下跳
 end;
 Query1.next; //记录下跳
end;
end;

procedure TForm1.TreeView1Click(Sender: TObject);
begin
If TreeView1.Selected.Level=1 then //判断节点层次
 begin
 With Query2 do
  Begin
   Close;
   SQL.clear;
   SQL.add('select * from parts where Description=:A');
   Parambyname('A').AsString:=Treeview1.selected.text;
   Open;
   End;
  Edit1.text:=Query2.fieldbyName('PartNo').AsString;
  Edit2.text:=Query2.fieldbyName('OnHand').AsString;
  Edit3.text:=Query2.fieldbyName('OnOrder').AsString;
  Edit4.text:=Query2.fieldbyName('Cost').AsString;
  Edit5.text:=Query2.fieldbyName('ListPrice').AsString;
end;
end;

end.