有关TTreeNode 添加data属性的问题

Type
  pRootNode: ^XRootNode;
  XRootNode = Record
           id:string;
           name:string;
           ......
           end;//end of record

用class不成吗？我还想继承这个的。type  PxTreeNode = ^XTreeNode;
  XTreeNode = class(TObject)
  private
  protected
  public
    name:String;
    id:String;
    nodeType: integer;
  end;  PxRootNode = ^XRootNode;
  XRootNode = class(XTreeNode)
  public
    subtype: integer;
    value: string;
  end;

New(pRootNode);
pRootNode^.id:= '';
^.name:= 'aaa';
root:= tvwProject.Items.AddObject(tvwProject.Selected,'aaa'，pRootNode);

procedure TfrmDesignerGeneral.ManageAllProject;
var
  s:String;
  root:TTreeNode;
begin
  tvwProject.Items.Clear;  New(pRootNode);  pRootNode^.id:= '';
  pRootNode^.name:= 'aaa';
  pRootNode^.nodeType:= 1;
  pRootNode^.subtype:= 0;
  pRootNode^.value:= '';  root:= tvwProject.Items.AddObject(tvwProject.Selected,'aaa',pRootNode);  tvwProject.Items.AddChild(root,'tmp');
end;可是当我把pRootNode^.*** 之类的注释掉就好了。类的定义在前面，为什么？我第一次用Delphi定义类

procedure TfrmDesignerGeneral.ManageAllProject;
var
  s:String;
  root:TTreeNode;
begin
  tvwProject.Items.Clear;
  New(pRootNode);
  pRootNode^.id:= '';
  pRootNode^.name:= 'aaa';
  pRootNode^.nodeType:= 1;
  pRootNode^.subtype:= 0;
  pRootNode^.value:= '';
  root:= tvwProject.Items.AddChildObject(tvwProject.Selected,'tmp',pRootNode);
  Dispose(pRootNode);
end;

指针和类不会用，别瞎用。
类是create的，不是new的

是这样，调试发现运行到
pRootNode^.id:= '';
时发现错误。id成员是父类的成员。在向父类成员赋值时出现错误。如果执行
pRootNode^.subtype:= 0;
则不会发生错误。后来定义了一个
rootNode: XRootNode;执行rootNode:= XRootNode.create;
pRootNode:= @rootNode
pRootNode^.id:= '';就好用了。那么，诸如
New(pRootNode);
getmem(pRootNode,sizeof(XRootNode));
pRootNode:= @XRootNode.Create;
这样的语句为什么不能起到为XRootNode的父类成员分配内存的效果？

我喜欢这样用
TuserNode=class(Tobject)
firstname:string;
lastName:string;
UserID:string;
end;aUser:=TuserNode.Create();
aUser.firstName='xxx';
aUser.lastName='xxx';
aUser.UserID='xxx';TreeView.Items.item[0].Data:=aUser;
TuserNode(TreeView.Items.item[0].Data).firstName;
TuserNode(TreeView.Items.item[0].Data).UserID;呵呵，感觉不到指针

to zhboy(孔方兄)
谢谢提出来，一时弄错了

给你一例子慢慢看吧。
对了，差点忘了最重要的一点：删除节点之前，一定要把Node.Data指向的
变量（内存）释放了！否则会造成内存泄漏的。
function funFreeTreeViewNodeData(aNode: TTreeNode): integer;
var
p: Pointer;
begin
Result := -1;
if Assigned(aNode.Data) then
begin
   try
     p := aNode.Data;
     Dispose(p);
     aNode.Data := nil;
   except
     on E: Exception do
       Application.MessageBox(PChar(E.Message),
         '释放树型节点指针(Data)时发生错误', 0);
   end;
end;
Result := 1;
end;// 删除节点时释放内存
procedure TGZLLLBMainFrm.trvGZLLreplyDeletion(Sender: TObject;
Node: TTreeNode);
begin
wintelconst.funFreeTreeViewNodeData(Node);
end;
{展开TreeView节点}procedure TGZLLLBMainFrm.trvGZLLreplyExpanding(Sender: TObject; Node:
TTreeNode;
var AllowExpansion: Boolean);
begin
if Node.Level <> 0 then
   funGetNodeChildren(1, Node);
end;{刷新TreeView节点,传递"层"参数,
aLevel=0:根节点；aLevel为其它值，非根节点}function TGZLLLBMainFrm.funGetNodeChildren(aLevel: Byte; aNode: TTreeNode):
Byte;
var
I, j: integer;
NodeData: PGZLLNodeData;
trvNode, curNode: TTreeNode;
begin
Result := 0;                          {失败}
try
   trvGZLLreply.Items.BeginUpdate;     {更改节点期间禁止刷新}
   case aLevel of
     {第一层不再使用！！！}
     0:                                {根节点，一次取两层的数据}
       begin
         {释放占用内存, 清除所有原来的节点}
         vChooseIndexL2 := -1;
         if trvGZLLreply.Items.Count > 0 then
         begin
           {for i := 0 to trvGZLLreply.Items.Count-1 do
             wintelconst.prcFreeNodeData(trvGZLLreply.Items[i],False);}
           for I := trvGZLLreply.Items.Count - 1 downto 0 do
             trvGZLLreply.Items[I].Delete;
         end;
         with adoqryGZLLL21 do         {取第一层节点数据}
         begin
           Active := False;
           Filter := '';
           Filtered := False;
           SQL.Clear;
           SQL.Append(wintelconst.cSQLGZLLLevel1); //cSQLLevel1 Format(,[0])
           Active := True;
           if not IsEmpty then
           begin
             for I := 0 to RecordCount - 1 do
             begin
               new(NodeData);
               NodeData^.ID := FieldByName('id').AsInteger;
               NodeData^.fjr := FieldByName('fjr').AsString;
               curNode := trvGZLLreply.Items.AddObject(nil,
                 FieldValues['llzt'], NodeData);
               {取第二层节点}
               with adoqryGZLLL22 do
               begin
                 Active := False;
                 //SQL.Clear;
                 //SQL.Append(Format(cSQLLevel2,[PGZLLNodeData(curNode.Data)^.id]));
                 Parameters.ParamValues['ID'] :=
                   PGZLLNodeData(curNode.Data)^.ID;
                 Active := True;
                 if not IsEmpty then
                 begin
                   for j := 0 to RecordCount - 1 do
                   begin
                     new(NodeData);
                     NodeData^.ID := FieldValues['id'];
                     NodeData^.fjr := FieldValues['fjr'];
                     trvGZLLreply.Items.AddChildObject(curNode,
                       FieldValues['llzt'], NodeData); //curCNode :=
                     Next;
                   end;                {end for(j)}
                 end;
                 Active := False;
               end;                    {end with adoqryGZLL2}
               Next;
             end;                      {end for(i)}
           end;
           Active := False;
           //EmptyRec := IsEmpty;
         end;                          {end with adoqryGZLL}
         Result := 1;
       end;                            {end case(0)}
     1: {非根节点，取本层的子节点以及孙节点，相当于刷新}
       begin
         trvNode := aNode;
         {如果有子节点，先把所有的删除}
         if trvNode.HasChildren then
         begin
           {for i := 0 to trvNode.Count-1 do
             wintelconst.prcFreeNodeData(trvNode.Item[i],False); }
           trvNode.DeleteChildren;
         end;
         with adoqryGZLLL21 do         {子节点}
         begin
           Active := False;
           Filter := '';
           Filtered := False;
           SQL.Clear;
           SQL.Append(Format(wintelconst.cSQLGZLLLevel2,
             [PGZLLNodeData(trvNode.Data)^.ID]));
           //SQL.Append(fun
           Active := True;
           Sort := 'id DESC';
           for I := 0 to RecordCount - 1 do
           begin
             new(NodeData);
             NodeData^.ID := FieldValues['id'];
             NodeData^.fjr := FieldValues['fjr'];
             curNode := trvGZLLreply.Items.AddChildObject(trvNode,
               FieldValues['llzt'], NodeData); //curCNode :=
             {取第二层节点}
             with adoqryGZLLL22 do
             begin
               Active := False;
               //SQL.Clear;
               //SQL.Append(Format(cSQLLevel2,[PGZLLNodeData(curNode.Data)^.id]));
               Parameters.ParamValues['ID'] :=
                 PGZLLNodeData(curNode.Data)^.ID;
               Active := True;
               Sort := 'id DESC';
               if not IsEmpty then
               begin
                 for j := 0 to RecordCount - 1 do
                 begin
                   new(NodeData);
                   NodeData^.ID := FieldValues['id'];
                   NodeData^.fjr := FieldValues['fjr'];
                   trvGZLLreply.Items.AddChildObject(curNode,
                     FieldValues['llzt'], NodeData); //curCNode :=
                   Next;
                 end;                  {end for(j)}
               end;
               Active := False;
             end;                      {end with adoqryGZLL2}
             Next;
           end;
           Active := False;
         end;                          {end with adoqryGZLL}
         Result := 1;
       end;                            {end case(1)}
   end;                                {end case}
finally
   trvGZLLreply.Items.EndUpdate;       {开始刷新}
end;
end;

调试易

有关TTreeNode 添加data属性的问题

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