生成树的问题？

Question

表名：TableName
字段：NodeNO(主键),ParentNO,NodeLevel,NodeType,NodeName
控件：Treeview
请问各位大侠如何生成树，树的层数不限，最好不用NodeLevel字段，如果实在不行也可用。

Answer 1

此程序没有用NodeLevel:  
TTreeViewData = record
       indexID : Integer;
       ParentID : Integer;
       NodeType: Integer;
  end;procedure TSQLTV.CreateTreeView(Node: TTreeNode; SQLStr: String; var TreeView: TTreeView);
var
  tmpQ: TADOQuery;
  tmpNode: TTreeNode;
  TVData: ^TTreeViewData;
begin
  tmpQ := TADOQuery.Create(nil);
  tmpQ.ConnectionString := ConStr;  try
    with tmpQ do
    begin
      Close;
      SQL.Clear;
      SQL.Add('select * from TreeView where ParentNo='+SQLStr);
      try
        Open;
      except
        ;
      end;      if RecordCount > 0 then
      begin
        First;
        while not Eof  do
        begin
          new(TVData);
          TVData.indexID := FieldByName('NodeNo').AsInteger;
          TVData.ParentID := FieldByName('ParentNo').AsInteger;
          tmpNode := Treeview.Items.AddChild(Node,FieldByName ('NodeName').Asstring);
          TVData.NodeType := FieldByName('NodeType').AsInteger;
          tmpNode.Data := TVData;
          CreateTreeView(tmpNode, FieldByName ('Index_id').Asstring, TreeView);
          Next;
        end;
      end;
    end;
  finally
    tmpQ.Free;
  end;
end;//从库中读取数据形成TreeView
procedure TSQLTV.OutputTreeView(var TreeView: TTreeView);
var
  Node: TTreeNode;
  tmpQ: TADOQuery;
  TVData: ^TTreeViewData;
begin
  TreeView.Items.Clear;
  try
    tmpQ := TADOQuery.Create(nil);
    tmpQ.ConnectionString := ConStr;
  except
    ;
  end;  tmpQ.Close;
  tmpQ.SQL.Clear;
  tmpQ.SQL.Add('select * from TreeView where parentNO = 0');
  try
    tmpQ.Open;
  except
    ;
  end;  if tmpQ.RecordCount > 0 then
  begin
    tmpQ.First;
    while not tmpQ.Eof do
    begin
      new(TVData);
      TVData.indexID := tmpQ.FieldByName('NodeNo').AsInteger;
      TVData.ParentID := tmpQ.FieldByName('ParentNO').AsInteger;
      TVData.NodeType := tmpQ.FieldByName('NodeType').AsInteger;
      Node := Treeview.Items.Add(nil, tmpQ.FieldByName ('NOdename').Asstring);
      Node.Data := TVData;
      CreateTreeView(node, tmpQ.FieldByName ('NodeNo').Asstring, TreeView);
      tmpQ.Next;
    end;
  end;
end;

Answer 2

var
  TVData : ^TTreeViewData;
  vType: Integer;
begin
    TVData := TreeView.Selected.Data;
    if TVData <> nil then
    begin
      vType := TVData.NodeType;
    end;
end;