关于动态增加、修改、删除树形结构的程序

    { Public declarations }
  end;

    const
  CTreeCodeFormat='122222';
  cTreeMaxLevel=6;
  CTreeRootTXT='所有图书';

var
  tsgzlfrom: Ttsgzlfrom;
  _err:integer;
  curUser:string[10];
  mystate:string;
  gNodeId:string;
  gNodelevel:integer;
  gNode:TtreeNode;
  mynode:array[0..6] of TTreenode;
  i,Already,CurMode:integer;
  currow:integer;
  iniFile:string;
  HasSub:String;

  level:Integer;

  implementation

uses bgNewunit;

{$R *.DFM}

procedure TtsgzlFrom.LoadTree(treeDB:TDBDataSet);//初始化树
var curID,nodeTxt:string;
    level,num:integer;
begin
    //初始化变量
    Screen.Cursor:=crHourGlass;
    tree.Enabled:=True;
    tree.Items.Clear;
    level:=1 ;
    num:=1;
    tree.items.clear;
    //设置根节点
    mynode[level]:=Tree.items.add(Tree.Topitem,cTreeRootTxt);
    mynode[level].ImageIndex:=0;
    mynode[level].SelectedIndex:=1;
    //遍历数据表，利用编码字段记录排序规律，依次添加树节点
    with TreeDb do
    begin
       try
       if not Active then open;
       first;
       while not Eof do
       begin
         curID:=trim(FieldByName('tsglb').AsString);
         nodeTxt:=curID+'-'+trim(FieldByName('tsglbn').AsString);
         level:=GetNodeLevel(cTreeCodeFormat,curID);
         //这里返回代码的层次数
         if level>0 then
         begin
  //增加下一节点时，用添加子节点的方法可轻松实现节点间的层次关系。
         //注意：这里的父节点是用当前节点的上一级节点mynode[level-1]
            mynode[level]:=Tree.Items.AddChild(Mynode[level-1],NodeTxt);
            mynode[level].ImageIndex:=2;
            mynode[level].SelectedIndex:=3;
         end;
         next;//下一条记录
       end;
       finally;
         close;
       End;
       mynode[1].expand(False);
       Screen.Cursor:=crHourGlass;
     end;
end;

function TtsgzlFrom.GetNodeLevel(sFormat,sCode:string):integer;
var i,iLen:integer;
begin
  level:=-1  ;
  iLen:=0;
  if (sFormat<>') and (sCode<>') then
    for i:=1 to Length(sFormat) do //分析编码格式，找出当前代码层次
    begin
      iLen:=iLen+StrToInt(sFormat[i]);
      if Length(sCode)=iLen then
      begin
        level:=i;
        break;
      end;
    end;
  result:=level;
end;

Function TtsgzlFrom.GetNodeItem(sCode:string):integer;//获得item
var i,iCount,val:integer;
    tmp:string;
begin
  Result:=0;
  iCount:=Tree.Items.Count;
  if iCount=0 then exit;
  val:=0;
  for i:=1 to iCount-1 do
  begin
     Tmp:=Tree.Items.Item[i].Text;
     Tmp:=Copy(Tmp,0,pos('-',Tmp)-1);
     if Tmp=sCode then begin
        val:=i;
        Break;
     end;
  end;
  result:=val;
end;

procedure TtsgzlFrom.UpdateTree(curNode:TTreenode; nodeTxt:string; state:string);
Begin
  if  state='add'   then
    begin
      curNode:=Tree.Items.addchild(curNode,nodeTxt);
      curNode.ImageIndex:=2;
      curnode.SelectedIndex:=3;
    end;
  if state='del' then  curNode.delete;
  if state='edi' then  curNode.Text:=nodeTxt;
end;