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Confused With Views

I'm a total newb when it comes to the Doc/View architecture . . . I mean, I understand the concept, I just can't implement anything beyond a simple SDI app with one view. Anyway, I have an example prog by someone else that I want to modify (as a "learning experience") to have a second view.

Basically, it's an SDI application with the author's version of a Tree/List control as its only view. I'm trying to add a second view on the right that is a list box (or list view, I guess).

Anyway, my first problem: I went into ClassWizard and clicked "New Class", then named it "CRightView" and said it should be derived from CListView. However, I get all sorts of errors when compiling:

RightView.cpp
error C2504: 'CListView' : base class undefined
error C2440: 'return' : cannot convert from 'class CRightView *' to 'class CObject *'
error C2653: 'CListView' : is not a class or namespace name
error C2065: 'classCListView' : undeclared identifier
error C2653: 'CListView' : is not a class or namespace name
error C2065: 'GetDocument' : undeclared identifier
error C2440: 'initializing' : cannot convert from 'int' to 'class CDocument *'
error C2653: 'CListView' : is not a class or namespace name
error C2653: 'CListView' : is not a class or namespace name

On another forum, they suggested that I add it as an MFC class. I did it again and was careful to select MFC class, but I still get the errors. What am I doing wrong?

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chensu

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rjahrman

ASKER

OK, it compiled after I did that. However, now that I've added the code from an article I read to it, I get an access violation when I try to run the program. The debugger went to this line in SetRowInfo:

m_pRowInfo[row].nIdealSize = cyIdeal;

My call to this function (that I think it's talking about) looks like so:

CFrameWnd::OnSize(nType, cx, cy);
CRect cr;
GetWindowRect(&cr);
if ( m_bInitSplitter && nType != SIZE_MINIMIZED )
      m_mainSplitter.SetRowInfo( 0, cy, 0 ); // RIGHT HERE!
      m_mainSplitter.SetColumnInfo( 0, (cr.Width()/4)*3, 50);
      m_mainSplitter.SetColumnInfo( 1, cr.Width() / 4, 50);
      m_mainSplitter.RecalcLayout();
}

What do I need to do?

chensu

Is m_pRowInfo valid? Is row out of range?

rjahrman

ASKER

I'm not sure . . . but in the MFC source, right before that there's an assert that looks like it detects that.

If it helps, here is the code I use to set up the splitter:

BOOL CMainFrame::OnCreateClient(LPCREATESTRUCT lpcs, CCreateContext* pContext)
{
      // TODO: Add your specialized code here and/or call the base class

      CRect cr;
      GetClientRect( &cr);

      if ( !m_mainSplitter.CreateStatic( this, 1, 2 ) )
      {
            MessageBox( "Error setting up splitter frames!", "Init Error!", MB_OK | MB_ICONERROR );
            return FALSE;
      }

      if ( !m_mainSplitter.CreateView( 0, 0, RUNTIME_CLASS(CNewTreeListCtrlView), CSize((cr.Width()/4)*3, cr.Height()), pContext ) )
      {
            MessageBox( "Error setting up splitter frames!", "Init Error!", MB_OK | MB_ICONERROR );
            return FALSE;
      }

      if ( !m_mainSplitter.CreateView( 0, 1, RUNTIME_CLASS(CRightView), CSize(cr.Width()/4, cr.Height()), pContext ) )
      {
            MessageBox( "Error setting up splitter frames!", "Init Error!", MB_OK | MB_ICONERROR );
            return FALSE;
      }

      m_bInitSplitter = TRUE;

      return TRUE;
}

chensu

What is the assert? Please copy it here.

rjahrman

ASKER

There _isn't_ an assert . . . that's just it. It exits with an access violation (probably caused by that array). What I meant was that the asserts above it should have caught it if that was the problem. Right?

chensu

What were the values of m_pRowInfo and row at that time?

rjahrman

ASKER

row is 0
m_pRowInfo:
all three values are "Error: expression cannot be evaluated"

rjahrman

ASKER

Also, m_nMaxRows is 1.

chensu

>m_pRowInfo:
> all three values are "Error: expression cannot be evaluated"

This means m_pRowInfo is invalid.

I think the problem is that OnSize() is actually called before CMainFrame::OnCreateClient(). So, at that point, the m_mainSplitter.CreateStatic() has not been called yet. The solution is to have a flag. You initialize the flag to false and set it to true after m_mainSplitter.CreateStatic() succeeds. In your OnSize(), check the flag. But it seems to me that you already have a flag m_bInitSplitter. Did you initialize it to FALSE?