VC多对话框界面程序，界面之间的切换问题

void CDlgTopDlg::OnButton1() 
{
	// TODO: Add your control notification handler code here
	
//	ShowWindow(SW_HIDE);	// If I hide the main dialog, dlgsub10.DoModal() won't work
	nResponse_sub10 = dlgsub10.DoModal();
	while (1)
	{
			if (nResponse_sub10 == IDOK)
			{
				// show sub11
				nResponse_sub11 = dlgsub11.DoModal();
				while (1)
				{
						if (nResponse_sub11 == IDOK)
						{
							// show sub12
							nResponse_sub12 = dlgsub12.DoModal();
							if (nResponse_sub12 == IDOK)
							{
								nResponse_sub11 = dlgsub11.DoModal();
							} 
							else if (nResponse_sub12 == IDCANCEL)
							{
								nResponse_sub11 = dlgsub11.DoModal();
							}
						}
						else if (nResponse_sub11 == IDCANCEL)
						{
							nResponse_sub10 = dlgsub10.DoModal();
							break;
						}
				}
			}
			else if (nResponse_sub10 == IDCANCEL)
			{
				//
			//	ShowWindow(SW_SHOW);	//As I will show the dialog in full screen, so maybe keeping it show doesn't matter
				break;
			}
	}

}

void CDlgTopDlg::OnButton2() 
{
	// TODO: Add your control notification handler code here
	
	
	nResponse_sub20 = dlgsub20.DoModal();
	if (nResponse_sub20 == IDOK)
	{
		// show sub
		
	}
	else if (nResponse_sub20 == IDCANCEL)
	{
		//
	}
}