怎样给treeview的data属性赋值？ (50分)

我定义了一个这样的结构来作为treeview.data的指针类型：　
type
indexpointer = ^Tnodedata;
Tnodedata = record
Nid: integer;
NpID: integer;
end;

然后想把两个数Nid=10,NPID=20赋给treeview.data，应怎么办？
　　我用下面的代码怎么老出错？
　　indexpointer(treeview1.selected.data)^.NID:=10;

请高手来看看！
　

1.new(indexpointer);
2.treeview1.addobject(nil,'test',indexpointer);
3.indexpointer(treeview1.items[0].data)^.NID:=10;

to　xiaolin0522,
这三句代码要一块用吗？
第二句是怎么回事？那个nil,'text'，各是什么意思？

var
Myindexpointer
MyNode: TTreeNode;
begin
New(Myindexpointer);
MyNode := TreeView1.AddObject(nil,'MyData',MyIndexpointer);
MyIndexpointer(MyNode.Data)^.Nid := 10;

function AddObject(Node: TTreeNode; const S: string; Ptr: Pointer): TTreeNode;

Description

The node is added as the last sibling of the node specified by the Node parameter. The S parameter specifies the Text property of the new node. The Ptr parameter specifies the Data property value of the new node. AddObject returns the node that has been added.

Note: The memory referenced by Ptr is not freed when the tree nodes object is freed.

TreeList.Items[index].Data := New(indexpointer);
with indexpointer(TreeList.Items[index].Data)^ do
begin
Nid := ;
NpID := ;
end;

谢谢大家，解决！