关于treeview控件的data属性！困扰多日，望高手指点！

[wangjun2000]

现有table和treeview控件
其中，table结构如下
myid:自动编号类型
菜单标题:string;
myparentid:integer;//指向myid,表明层次关系

先定义记录类型
type
PMyList = ^AList;
AList = record
MyParendID: string;
xxx:integer; //为验证节点值特意增加的测试域
MyNodeP: TTreeNode ;
end;



//定义生成节点的过程
procedure Tform1.MyNode(MyParentID:string;MyNodeT:TTreeNode);

var
ATempList: TList;
I: Integer;
ARecord:PMyList;
s:string;
node:TTreeNode;
begin
ADOTable1.Filtered:=true;
ADOTable1.Filter:=' MYParentID ='+MyParentID;
if ADOTable1.RecordCount<1 then exit;
ATempList := TList.Create;
try
ADOTable1.First;
while not ADOTable1.Eof do
begin
New(ARecord);
s:='('+ADOTable1.fieldbyname('MyID').AsString +')'+ ADOTable1.fieldbyname('菜单标题').AsString ;
node:= TreeView1.Items.AddChild(MyNodeT ,s) ;
ARecord^.MyParendID:= ADOTable1.fieldbyname('myid').AsString;
Arecord^.MyNodeP :=node;
Arecord^.xxx:=222;
node.Data :=Arecord; //将记录值赋给节点的data属性
caption:=caption+inttostr(pmylist(node.data)^.xxx) ;
ATempList.Add(Arecord);
ADOTable1.Next;
end;
for I :=0 to ATempList.Count - 1 do
begin
Arecord:=ATempList.Items[i];
MyNode(Arecord^.MyParendID,Arecord^.MyNodeP );
end;
finally
for I := 0 to ATempList.Count - 1 do
Dispose(ATempList[I]);
ATempList.Free;
ADOTable1.Filtered:=false;
end;
end;


procedure TForm1.FormCreate(Sender: TObject);
begin
MyNode('0',nil );
end;

//检查节点的data属性
procedure TForm1.Button1Click(Sender: TObject);
var
CurItem: TTreeNode;
begin
listbox1.Clear;
CurItem := TreeView1.Items.GetFirstNode;
while CurItem<>nil do
begin
showmessage(curitem.Text); //运行结果正常
showmessage(pmylist(curitem.Data )^.MyParendID ); //报AV错,取不到值
showmessage(inttostr(pmylist(curitem.Data )^.xxx)); //取到了值,有部分是生成节点时的222,另外一部分不是.
CurItem := CurItem.GetNext;
end;
end;


现请高手指点，Button1Click中那两句取节点data属性的执行结果为什么不正确？

[cowboy1999]

type
PMyList = ^AList;
AList = record
MyParendID: string;
xxx:integer; //为验证节点值特意增加的测试域
MyNodeP: TTreeNode ;
end;

可能是这个类型定义的问题，MyParendID定义最好用Array of char或者指定String长度，例如：MyParentID: String[10]；不指定MyParentID的String长度，在new（aPMyList）时，编译器不知道申请多大的内存块块！

[gobiz]

============================================================
加上packed试试！
============================================================

type
PMyList = ^AList;
AList = packed record
MyParendID: string;
xxx:integer; //为验证节点值特意增加的测试域
MyNodeP: TTreeNode ;
end;

[Rail100]

这个语句放在销毁treeview时才执行。
for I := 0 to ATempList.Count - 1 do
Dispose(ATempList[I]);

[xthmpro_cn]

建议搂主研究一下OnCreateNodeClass事件，并注意var NodeClass: TTreeNodeClass参数。你可以从TTreeNode中重载一个类，在这个事件中将你的类赋值给NodeClass，访问节点时，强制转换你自己的类即可。
如果有问题，可以继续提问。

[cdsgajxlp]

参考
unit Unit1;

interface

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

type
PMyList = ^AList;
AList = packed record
MyParendID: string;
xxx:integer; //为验证节点值特意增加的测试域
end;
TForm1 = class(TForm)
TreeView1: TTreeView;
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);

var
MyList : PMyList;
t : TtreeNode;
begin
new(mylist);
MyList.MyParendID:='sdf';
MyList.xxx:=1;
TreeView1.Items.AddChildObject(nil,mylist.MyParendID,Tobject(MyList));
end;

procedure TForm1.Button2Click(Sender: TObject);
var
index : integer;
begin

Showmessage(PMyList(TreeView1.Items[0].Data)^.MyParendID)
end;

end.

[cdsgajxlp]

估计节点没有加进去
showmessage(pmylist(curitem.Data )^.MyParendID ); //报AV错,取不到值