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How to change a view from a dialog box

jhum
jhum asked
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Last Modified: 2012-05-04
Can somebody tell me how to make changes to a view from a dialog box. That is I want to draw something on a view when the some textbox data in my dialog box changes. How do i relate this textbox's (IDC_EXIT10 which is part of cConfDialog) event (ENCHANGE event?) to do something (for example draw a line) in  a view (CJLPView)?

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Commented:
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Commented:
Hi Phillip,

You really can't do it that way. m_pView  would point to the dlgTest instead of the view. You should store the address to the view in a variable before you declare it, something like this:

        CView* tempViewptr;
      tempViewptr=this;
      CConfDlg dlg;
      dlg.m_pView =tempViewptr;
      dlg.DoModal();

Thanks for the help and here's your boring 5 points :-)

Commented:
Ah... Not true.

The 'this' pointer is the 'this' of the calling function, such as

CView::OnConfDlg( )
{
   CConfDlg dlg;
   dlg.m_pView = this;
   dlg.DoModal( );
}

and is NOT the "this" of CConfDlg or 'dlg'.  

I Promise!  I do it all the time!  Just because the CConfDlg is created doesn't change the scope of the 'this'.  If you wanted the this of the CConfDialog, you would have to do a "dlg.this".

Phillip

Author

Commented:
Hi Phillip,

I tried just that . Dunno why it pointed to the dialog box. I think as soon as you declare a new instance of the dialog box, the constructor is run and therefore the 'this' pointer is already initialized. Maybe I'm wrong. More questions are sure to be on their way, and i'll try to make them more than 5 pointers :-)!

Commented:
"this" is definitely the view's "this" not the dialog's "this".  I'm not sure what you're seeing!  It is true that the 'this' pointer is initialized, but it's initialized for the class that's calling it.

Cool about the points though!

Phillip



Commented:
As a matter of fact, when you do a dlg.m_pView = this,  if the 'this' isn't the same class as your m_pView, then you would get a compilation error!

Phillip

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