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用树型结构表示科目代码的一种高效算法(2) unit Main;
interface
uses
Windows, Messages, SysUtils, Classes, GraphiCS,
Controls, Forms, Dialogs,
Db, DBTables, ComCtrls, ImgList, StdCtrls;
type
TForm1 = class(TForm)
tvwCode: TTreeView;
tblCode: TTable;
ImageList1: TImageList;
btnClose: TButton;
procedure FormCreate(Sender: TObject);
procedure btnCloseClick(Sender: TObject);
private
{ Private declarations }
function LoadCode(crTbl:TDBDataSet):Integer;
function GetLevel(sFormat,sCode:String):Integer;
public
{ Public declarations }
end;
var
Form1: TForm1;
const
SCodeFormat = '322222'; //科目代码结构
SFirstNodeTxt = '科目代码'; //首节点显示的文字
implementation
{$R *.DFM}
//以下函数是本文的重点部分，
其主要功能是用一循环将Code.db表中的
//科目代码和科目代码名称显示出来
function TForm1.LoadCode(crTbl:TDBDataSet):Integer;
var NowID,sName,ShowTxt:String;
i,Level:Integer;
MyNode:array[0..6]of TTreeNode;
//保存各级节点，最长支持6级(重点)
begin
Screen.Cursor:=crHourGlass;
Level:=0;
With crTbl do
begin
try
if not Active then Open;
First;
tvwCode.Items.Clear;
//以下是增加第一项
MyNode[Level]:=tvwCode.Items.Add
(tvwCode.TopItem,SFirstNodeTxt);
MyNode[Level].ImageIndex:=0;
MyNode[Level].SelectedIndex:=0;
//以上是增加第一项
While Not Eof do
begin
NowID:=Trim(FieldByName('aCode').AsString);
ShowTxt:=NowID+' '+FieldByName('aName').AsString;
Level:=GetLevel(SCodeFormat,NowID);
//返回代码的级数
//以下是增加子项
//以下用上一级节点为父节点添加子节点
if Level>0 then//确保代码符合标准
begin
MyNode[Level]:=tvwCode.Items.AddChild
(MyNode[Level-1],ShowTxt);
MyNode[Level].ImageIndex:=1;
MyNode[Level].SelectedIndex:=2;
end;
//以上是增加子项
Next;
end;
finally
Close;
end;
end;
MyNode[0].EXPand(False);//将首节点展开
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