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Getting ahold of a Window

Posted on 1998-09-25
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Last Modified: 2013-11-20
I need to call a member function of a view class.  I am
calling it from a function that is totally unrelated and in
a separate file of (non-classed) functions.  How do I get
ahold of the view's instance so I can call the function?  
It isn't static.
     
There is always one instance of this view open.
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Question by:appleby
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4 Comments
 
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Accepted Solution

by:
Answers2000 earned 280 total points
ID: 1322616
You need to be able to get a pointer to the view as you realize

Why not add a public static member to the view class :

In view header

class CSomeView : public CView
{
 //etc
public:
  static CSomeView * pTheView ;
// etc
} ;

In the view's cpp

CSomeView * CSomeView::pTheView = NULL ;

In the constructor of the view, assign pTheView to the this ptr
In the destructor of the view, assign it back to NULL

CSomeView::CSomeView( ..etc.. )
{
 //etc
 pTheView = this ;
}

CSomeView::~CSomeView()
{
 pTheView = NULL ;
}


Now in the function that needs to call the view's function you can do this

void SomeFunction( ..etc.. )
{
  ASSERT_VALID( CSomeView::pTheView ) ;
  CSomeView::pTheView->FunctionToCall( ..etc.. ) ;
}

0
 

Expert Comment

by:umarama
ID: 1322617
Using Afx calls you can get a pointer to the current active view.
m_pView      = ((CFrameWnd *)AfxGetMainWnd())->GetActiveView();

Also, you can use the following calls to get other imp ptrs.
m_pMainWnd = (CFrameWnd*)AfxGetMainWnd();
m_pApp         = AfxGetApp();


0
 

Author Comment

by:appleby
ID: 1322618
Answers2000, what is going on with that first line you suggest adding to the view's .cpp?  
 
CSomeView * CSomeView::pTheView=NULL;

I've never seen this type of syntax before.  Why is it necessary, instead of just going right to the constructor?
0
 

Author Comment

by:appleby
ID: 1322619
I get it - just an initializer.  Ok thanks!
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