如何让主窗体不显示时子窗体最小化时程序能缩至任务栏？(50分)

主窗体是登陆界面，登陆成功后，主窗体消失，子窗体显示，但最小化是无法缩至任务栏
如何解决此问题？

这个问题实现很麻烦,我实现了,具体方法是
1.把最小化消息传给Application,代码如下
procedure TChildForm.WMSysCommand(var Message:TWMSysCommand);
begin
case Message.CmdType of
SC_MINIMIZE:
if fsModal in FormState then
//如果窗体是模式显示就不能用PostMessage
Application.Minimize
else
PostMessage(Application.Handle,0,SC_MINIMIZE,0);
else
inherited;
end;
end;
2.拦截应用程序的消息,代码如下
procedure TMDIMainForm.AppMessageHandler(var Msg:TMsg;var Handled:boolean);
var
i:integer;
begin
case Msg.wParam of
SC_MINIMIZE:
begin
if Assigned(Screen.ActiveForm) then
SetWindowPos(Application.Handle,Screen.ActiveForm.Handle,
Screen.ActiveForm.Left,Screen.ActiveForm.Top,
Screen.ActiveForm.Width,0,SWP_SHOWWINDOW);
DefWindowProc(Application.Handle,WM_SYSCOMMAND,SC_MINIMIZE,0);
end;
SC_RESTORE :
begin
if Assigned(Screen.ActiveForm) then
SetWindowPos(Application.Handle,Screen.ActiveForm.Handle,
Screen.ActiveForm.Left,Screen.ActiveForm.Top,
Screen.ActiveForm.Width,0,SWP_SHOWWINDOW);
DefWindowProc(Application.Handle,WM_SYSCOMMAND,SC_RESTORE,0);
end;
end;
Handled:=false;
end;
3.把2的过程与应用程序相关联,代码加在工程文件中
Application.OnMessage:=MDIMainForm.AppMessageHandler;

谢谢回答，那么怎样在子窗体中调用过程WMSysCommand(var Message:TWMSysCommand);

忘记说了
TChildForm = class(TForm)
private
//下面这句,拦截Windows消息
procedure WMSysCommand(var Message:TWMSysCommand);message WM_SYSCOMMAND;
protected
public
end;

我懂得你的意思了，非常感谢你的回答！
给你分数！