ASSERT when opening dialog box

[bkelly]

Environment: Windows XP Pro, Visual Studio 2008, MFC, C++

I have regressed since my last post and now am getting an Assert when I click a button to open a second dialog box.
Note: I cannot cut and paste from my work computer to my internet computer so please forgive any obvious typos.
In the main window .h file I have:

…
C_Logging_Control *mp_C_Logging_Control; // the class of the new dialog box
…

And in the .cpp file I have:

BOOL CAR2_Messasge_AppDlg::OnInitDialog() 
{
…
    // create the class that owns (??) the new dialog
   // I put a break point in C_Logging_Control constructor and it looks ok as it starts up.
mp_C_Logging_Control = new C_Logging_Control;
…. }

….  Much later, the code to open the new dialog
Void C_AR2_Messasge_AppDlg::OnBnClickedBtnOpenLogControl()
{
      // I will discuss these four lines in a moment
   bool test = false;
   bool window_value = ::IsWindows( m_hWnd);
   if( m_pCtrlSite != Null )
      test = true;

   if( mp_C_Logging_Control != NULL )
      mp_C_Logging_Control->ShowWindow( SW_SHOW );
}

Everything works until the call to ShowWindow which generates an ASSERT. I step into the ShowWindow code and the assert is in winocc.cpp and the code is:

BOOL CWnd::ShowWindow( int nCmdShow )
{
   ASSERT( ::IsWindow( m_hWnd) || (m_pCtrlSite != Null) );
…
}

This is the ASSERT that halts everything.
I took that ASSERT line of code, broke it up, and put it into my code that calls ShowWindow. That’s the four lines where I said they would be discussed in a moment.
I was a little bit surprised that it compiled, but that’s cool.
Bool window_Value is true after the call to IsWindows( m_hWnd )
As I read it, that means that the assert gets a true and should not bomb out.

So,…, are those four noted lines valid when I put them in my code?
Can someone detect the error on my part?

After another hour of work, the answer to the first question is No! Here is why:
I copied winocc.cpp into my project, adjusted its include files to reference the normal place, then broke up the ASSERT and discovered that ::IsWindow( m_hWnd) returns a false. Its OK in my code, but once deep down into the dialog’s code, its not. (I think that is the case.)

But now I don’t know what that means or how to fix it. Can someone clue me in on this?

Thank you for your time.

EDIT: I just found someing in some example code that translates to this in my code:

 mp_C_Logging_Control->Attach( hWnd );

The problem is that I don'w know the general meaning of hWind and what I need to use in my code. Is this the answer or is it something else.