treeview控件问题

Question

我在程序中用了一个treeview控件，他的node都要存到数据库中去，在数据库中有他的唯一代码，所以每次增加时我用的时item.addchildobject()并定义了一个指针
指针中有代码项，在展开时是对的，但是，在 chang时得出的代码是最后一个加入的代吗，这是怎么问题？？？？ 
原吗如下：
PNodeData = ^NodeData;
      NodeData=record
      nodeCaption:string;
      nodeId:integer;
     end;-----------------
function TGngz_Form.HasChildrenNode(nodeid:integer):boolean;
var
 query1:TADOQuery;
begin
query1:=TADOQuery.Create(self);
query1.Connection:=dm.ADOConnection1;
with query1 do
   begin
   close;
   sql.Clear;
   sql.Add('select * from tree where ParentID=:nodeid');
   parameters.ParamByName('nodeid').Value:=nodeid;
   prepared;
   open ;
   if recordcount<>0 then
    result:=true
    else
    result:=false;
    close;
    end;
query1.Free;
end;
procedure TGngz_Form.TreeView1Expanding(Sender: TObject; Node: TTreeNode;  //-展开
  var AllowExpansion: Boolean);var
nodeid:integer;
nodeptr:PnodeData;
nodeptr1:PnodeData;
adoquery_treeNode:Tadoquery;
childnode:TTreeNode;
itemstr:string;
i:integer;
hasChild:Boolean;
begin
adoquery_treeNode:=Tadoquery.Create(self) ;
adoquery_treeNode.Connection:=dm.ADOConnection1;
nodeptr:=node.Data ;
nodeid:=nodeptr.nodeId;
showmessage(inttostr(nodeid));
for i:=0 to node.Count-1 do
   node.DeleteChildren;
with adoquery_treenode do
   begin
    close;
    sql.Clear;
    sql.Add('select * from tree where parentId=:nodeid and nodeAtt=1');
    parameters.ParamByName('nodeid').Value:=nodeid;
    open;
    if recordcount<>0 then
     begin
     new(nodeptr1);
     first ;
     //showmessage(inttostr(recordcount));
     while not eof do
     begin
       itemstr:=trim(fieldbyname('nodeCaption').AsString);
       nodeptr1.nodeCaption:=itemstr;
       nodeptr1.nodeId:=fieldbyname('Nodeid').AsInteger;
       childNode:=treeview1.Items.AddChildObject(Node,itemstr,nodeptr1);
       childnode.ImageIndex:=2;
       childnode.SelectedIndex:=4;
       hasChild:=HasChildrenNode(nodeptr1.nodeId);
       if hasChild=true then
         begin
         childNode.HasChildren:=true;
         //childnode.Selected;
         end
       else
         childNode.HasChildren:=false;
       next;
       end;
     end;
     close;
   end;
  // dispose(nodeptr1)
  end;
procedure TGngz_Form.TreeView1Changing(Sender: TObject; Node: TTreeNode;//------
  var AllowChange: Boolean);
var
nodeptr:PNodeData;             //指针
nodeid:integer;
query_listnode:TAdoquery;
//nIcon:integer;
xm:string;                    //项目
NAtt:integer;
lb:string;                   //类型
bh: string;                  //编号
desc:string  ;            //描述
ListItem: TListItem;
id:integer;
//i:integer;
nodeptr1:pnodedata;
begin
 nodeptr:=node.Data;;
 nodeid:=nodeptr^.nodeId; //父节点编号
 //showmessage(nodeptr^.nodeCaption);
 query_listnode:=Tadoquery.Create(self);
 query_listnode.Connection:=dm.ADOConnection1;
 listview1.Items.Clear;
 with query_listnode do
   begin
    close;
    sql.Clear;
    sql.Add('select * from tree where ParentID=:nodeid');
    parameters.ParamByName('nodeid').Value:=nodeid;
    prepared;
    open ;
    if recordcount<>0 then
     begin
     //setlength(listitemarray,recordcount);
     first;
     new(nodeptr1);
      //i:=1;
     while not eof do
        begin
          id:=fieldbyname('Nodeid').AsInteger;
          xm:=trim(fieldbyname('NodeCaption').AsString);
          bh:=trim(fieldbyname('DemandNo').AsString);
          nodeptr1.nodeCaption:=xm;
          nodeptr1.nodeId:=id;
          //listitemarray.nodeCaption:=xm;
          //listitemarray.nodeId:=id;
          desc:=trim(fieldbyname('NodeDesc').AsString);
          //nIcon:=fieldbyname('IconNo').AsInteger;
          NAtt:=fieldbyname('NodeAtt').AsInteger;
          if NAtt=1 then
             lb:='项目'
           else
             lb:='项目组' ;         listitem:=listview1.Items.Add;
         listitem.Data:=nodeptr1;
         listitem.Caption:=xm;
         listitem.SubItems.Add(bh);
         listitem.SubItems.Add(lb);
         listitem.SubItems.Add(desc);
         //i:=i+1   ;
         next ;
        end;
      end;
     end;
 end;