Solved

SubclassDlgItem on Property Page: failing on ASSERT

Posted on 2001-08-02
2
979 Views
Last Modified: 2013-11-20
I'm trying to dynamically subclass a field on a property page.  The code looks like this:

  BOOL CMyPropertyPage::OnInitDialog()
  {
    CPropertyPage::OnInitDialog();
    m_myedithandler.SubclassDlgItem(IDC_MYEDIT,this);
    return TRUE;  
  }

The SubclassDlgItem() fails on an ASSERT in

  BOOL CWnd::Attach(HWND hWndNew)
  {
    ASSERT(m_hWnd == NULL);                       //OK
    ASSERT(FromHandlePermanent(hWndNew) == NULL); //fails
    ...

FromHandlePermanent returns a non-NULL pWnd, presumbably because the control in question is already in the permanent map.

I've used the same override logic on an edit field in a regular dialog (derived from CDialog rather than CPropertyPage) without any problem.  Is there something special about subclassing on a property page?  Or can someone point me to something else I am doing wrong?
0
Comment
Question by:hansenk
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
2 Comments
 
LVL 49

Accepted Solution

by:
DanRollins earned 300 total points
ID: 6347355
The ClassWizard has created a variable (presumeably named m_myedithandler and presumably of a class derived from CEdit).  

CPropertyPage::OnInitDialog() during its DDX phase has already subclassed that control.

What you need to do is use the ClassWizard to remove that variable (that will remove the DDX_Control() call), then add it back manually in the CMyPropertyPage .h file.

public:
   CMyPropertyPage();   // standard constructor
   ~CMyPropertyPage();

   // added here, subclassed in OnInitDialog
   CMyEditHandler m_myedithandler;

-- Dan
0
 
LVL 49

Expert Comment

by:DanRollins
ID: 6352350
yore welcum
-- Dan
0

Featured Post

Secure Your Active Directory - April 20, 2017

Active Directory plays a critical role in your company’s IT infrastructure and keeping it secure in today’s hacker-infested world is a must.
Microsoft published 300+ pages of guidance, but who has the time, money, and resources to implement? Register now to find an easier way.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
MFC Dialog 9 53
Question regarding Copy/Paste 16 98
viewing source code from eclipse 13 110
sum67 challenge 35 116
Introduction: Finishing the grid – keyboard support for arrow keys to manoeuvre, entering the numbers.  The PreTranslateMessage function is to be used to intercept and respond to keyboard events. Continuing from the fourth article about sudoku. …
In this post we will learn different types of Android Layout and some basics of an Android App.
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…

726 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question