getting the active view in MDI + Doc/View application

From:

"harshalshete@gmail.com" <harshalshete@gmail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

5 Jun 2006 02:03:01 -0700

Message-ID:

<1149498181.789361.217190@j55g2000cwa.googlegroups.com>

hi group,

i want to get active view pointer and call it's member function

void CMainFrame::OnBuild()
{
        CChildFrame* pChild = (CChildFrame *)MDIGetActive();
    if(pChild)
    {
        CTritonSpiritBoardView *pView = (CTritonSpiritBoardView
*)pChild->GetActiveView();
        if(pView)
        {
            pView->HighLightLine(Line);
        }
    }
}
in this function it work's fine.it's a message handler for one menu
item.
but now if i want to call the activeview's this function from some
other
class then it gives assertion on MDIGetActive.

//if i try it on dialog boxes OnOk function then it asserts
void CBoard::OnOk()
{
     CMainFrame *pFrame = (CMainFrame *)AfxGetApp()->m_pMainWnd;
     if(pFrame)
     {
        CChildFrame* pChild = (CChildFrame
*)pFrame->MDIGetActive();//here inside
    if(pChild)
    {
        CTritonSpiritBoardView *pView = (CTritonSpiritBoardView
*)pChild->GetActiveView();
        if(pView)
        {
            pView->HighLightLine(Line);
        }
    }

     }
}

i didnot got this behaviour
and not only this if i create a public member function
in CMainFrame as Try()

void CMainFrame::Try()
{
     CChildFrame* pChild = (CChildFrame *)MDIGetActive();//here inside
    if(pChild)
    {
         CTritonSpiritBoardView *pView = (CTritonSpiritBoardView
                               *)pChild->GetActiveView();
        if(pView)
        {
            pView->HighLightLine(Line);
        }
    }

}

then also it asserts?
WHY like this?

if anyone know's please tell me.

Thank's and regards
harshal shete