Show/Hide Static Panes

MFC static splitter windows have a significant limitation. Their panes can’t be hidden or shown dynamically. To solve the problem I overrode the CSplitterWnd. The new class can hide a splitter window column. Sure, it’s only one approach to the problem, but it’s a good example anyway.

//////////////////////////////////////////////////////////////////
//
// splitex.h
// (c) 1997, Oleg G. Galkin
class CSplitterWndEx : public CSplitterWnd
{
protected:
   int m_nHidedCol;    // hide column number, -1 if all columns
                       // are shown
public:
   CSplitterWndEx();
   void ShowColumn();
   void HideColumn(int colHide);
// ClassWizard generated virtual function overrides
   //{{AFX_VIRTUAL(CSplitterWndEx)
   //}}AFX_VIRTUAL
// Generated message map functions
protected:
   //{{AFX_MSG(CSplitterWndEx)
      // NOTE – the ClassWizard will add and remove member
      //        functions here.
      //}}AFX_MSG
    DECLARE_MESSAGE_MAP()
};
//////////////////////////////////////////////////////////////////
//
// splitex.cpp
// (c) 1997, Oleg G. Galkin
#include “stdafx.h”
#include “splitex.h”
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
//////////////////////////////////////////////////////////////////
/
// CSplitterWndEx
CSplitterWndEx::CSplitterWndEx() :
    m_nHidedCol(-1)
{
}
void CSplitterWndEx::ShowColumn()
{
   ASSERT_VALID(this);
   ASSERT(m_nCols < m_nMaxCols);
   ASSERT(m_nHidedCol != -1);
   int colNew = m_nHidedCol;
   m_nHidedCol = -1;
   int cxNew = m_pColInfo[m_nCols].nCurSize;
   m_nCols++;    // add a column
   ASSERT(m_nCols == m_nMaxCols);
   // fill the hidden column
   int col;
   for (int row = 0; row < m_nRows; row++)
   {
      CWnd* pPaneShow = GetDlgItem(
         AFX_IDW_PANE_FIRST + row * 16 + m_nCols);
      ASSERT(pPaneShow != NULL);
      pPaneShow->ShowWindow(SW_SHOWNA);
      for (col = m_nCols – 2; col >= colNew; col–)
      {
         CWnd* pPane = GetPane(row, col);
         ASSERT(pPane != NULL);
         pPane->SetDlgCtrlID(IdFromRowCol(row, col + 1));
      }
      pPaneShow->SetDlgCtrlID(IdFromRowCol(row, colNew));
   }
   // new panes have been created — recalculate layout
   for (col = colNew + 1; col < m_nCols; col++)
      m_pColInfo[col].nIdealSize = m_pColInfo[col – 1].nCurSize;
   m_pColInfo[colNew].nIdealSize = cxNew;
   RecalcLayout();
}
void CSplitterWndEx::HideColumn(int colHide)
{
   ASSERT_VALID(this);
   ASSERT(m_nCols > 1);
   ASSERT(colHide < m_nCols);
   ASSERT(m_nHidedCol == -1);
   m_nHidedCol = colHide;
   // if the column has an active window — change it
   int rowActive, colActive;
   if (GetActivePane(&rowActive, &colActive) != NULL &&
       colActive == colHide)
   {
      if (++colActive >= m_nCols)
         colActive = 0;
      SetActivePane(rowActive, colActive);
   }
   // hide all column panes
   for (int row = 0; row < m_nRows; row++)
   {
      CWnd* pPaneHide = GetPane(row, colHide);
      ASSERT(pPaneHide != NULL);
      pPaneHide->ShowWindow(SW_HIDE);
      pPaneHide->SetDlgCtrlID(
         AFX_IDW_PANE_FIRST + row * 16 + m_nCols);
      for (int col = colHide + 1; col < m_nCols; col++)
      {
         CWnd* pPane = GetPane(row, col);
         ASSERT(pPane != NULL);
         pPane->SetDlgCtrlID(IdFromRowCol(row, col – 1));
      }
   }
   m_nCols–;
   m_pColInfo[m_nCols].nCurSize = m_pColInfo[colHide].nCurSize;
    RecalcLayout();
}
BEGIN_MESSAGE_MAP(CSplitterWndEx, CSplitterWnd)
//{{AFX_MSG_MAP(CSplitterWndEx)
   // NOTE – the ClassWizard will add and remove mapping macros here.
//}}AFX_MSG_MAP
END_MESSAGE_MAP()