★★★我从TDBGridEh扩展的一个组件，半路出了点问题，进来帮我看看！★★★

[arraiy]

组件类名：TDBGridEhHw，继承自TDBGridEh类
功能：在TDBGridEh实例上点击右键，可以弹出快捷菜单，功能分别是：新增记录，删除记录，打印当前表格，导出当前表格中的内容为...　4个功能，但是在做打印的时候出问题了．问题是要设置TPrintDBGridEh实例的DBGridEh属性，但现在我的新组件TDBGridEhHw不是TDBGridEh了，应该怎么搞定呀？
下面是我的原代码：大家帮我看看：
unit DBGridEhHw;

interface

uses
Windows, Messages, SysUtils, Classes, Controls, Grids, DBGridEh, PrnDbgeh, Dialogs, Menus, DB;

type
TDBGridEhHw = class(Tdbgrideh)
private
{ Private declarations }
protected
{ Protected declarations }
procedure AddOnClick(Sender: TObject);
procedure DelOnClick(Sender: TObject);
procedure PrintOnClick(Sender: TObject);
procedure ExportOnClick(Sender: TObject);
public
HwPopupMenu: TPopupMenu;
HwMenuAdd: TMenuItem;
HwMenuDel: TMenuItem;
HwMenuPrint: TMenuItem;
HwMenuExport: TMenuItem;
HwMenuItemLine: TMenuItem;
HwEhprint: TPrintDBGridEh;
{ Public declarations }
constructor Create(AOwner: TComponent); override;
destructor destroy; override;
published
{ Published declarations }
end;

procedure Register;

implementation

procedure TDBGridEhHw.AddOnClick(Sender: TObject);
begin
showmessage('插入一条新记录');
if (DataSource.DataSet.Active) and ((DataSource.DataSet.State = dsEdit) or (DataSource.DataSet.State = dsInsert)) then
begin
DataSource.DataSet.Append;
end;
end;

procedure TDBGridEhHw.DelOnClick(Sender: TObject);
begin
showmessage('删除当前记录');
if (DataSource.DataSet.Active) and ((DataSource.DataSet.State = dsEdit) or (DataSource.DataSet.State = dsInsert)) then
begin
DataSource.DataSet.Delete;
end;
end;

procedure TDBGridEhHw.PrintOnClick(Sender: TObject);
begin
showmessage('打印当前表格');
if (DataSource.DataSet.Active) and (DataSource.DataSet.RecordCount > 0) then
HwEhprint.Preview;
end;

procedure TDBGridEhHw.ExportOnClick(Sender: TObject);
begin
showmessage('导出为其他文件');
end;

constructor TDBGridEhHw.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
if not (csDesigning in self.ComponentState) then
begin
if self.PopupMenu = nil then
begin
Hwehprint := TPrintDBGridEh.Create(self); //创建一个TPrintDBGridEh对象，并且与TDBGridEh实例关联，实现表格打印
HwEhprint.DBGridEh := ?; //现在问题出在这儿，因为HwEhprint.DBGridEh必须是一个TDBGridEh类型
//，而目前我的是TDBGridEhHw，它是从TDBGridEh继承下来的，此时想个
//什么办法来设置这个属性？
HwPopupMenu := TPopupMenu.Create(self); //创建快捷菜单

HwMenuAdd := TMenuItem.Create(self); //创建子菜单
HwMenuAdd.Caption := '新增记录';
HwMenuAdd.OnClick := AddOnClick;

HwMenuDel := TMenuItem.Create(self); //创建子菜单
HwMenuDel.Caption := '删除记录';
HwMenuDel.OnClick := DelOnClick;

HwMenuPrint := TMenuItem.Create(self); //创建子菜单
HwMenuPrint.Caption := '打印...';
HwMenuPrint.OnClick := PrintOnClick;

HwMenuExport := TMenuItem.Create(self); //创建子菜单
HwMenuExport.Caption := '导出文件...';
HwMenuExport.OnClick := ExportOnClick;

HwPopupMenu.Items.Add(HwMenuAdd); //加入子菜单
HwPopupMenu.Items.Add(HwMenuDel);
HwPopupMenu.Items.Add(HwMenuPrint);
HwPopupMenu.Items.Add(HwMenuExport);

self.PopupMenu := HwPopupMenu;
end;
end;
end;

destructor TDBGridEhHw.destroy;
begin
HwPopupMenu.Free;
inherited destroy;
end;

procedure Register;
begin
RegisterComponents('Hw', [TDBGridEhHw]);
end;
end.

[arraiy]

大家进来帮我看看呀！在线等！

[blankman]

呵呵，没有用过这个控件，也没有这么使用过，
我还是觉得直接使用 sql 语句方便灵活得多