Fast Track Visual C++ 6.0 Programming
(Publisher: John Wiley & Sons, Inc.)
Author(s): Steve Holzner
ISBN: 0471312908
Publication Date: 09/01/98

Listing 7.2 ShareMemView.h and ShareMemView.cpp

// ShareMemView.h : interface of the CShareMemView class
//
/////////////////////////////////////////////////////////////////////////////

#if
!defined(AFX_SHAREMEMVIEW_H__BFF33AB7_A398_11D1_887F_D42B07C10710__INCLUDED_)
#define AFX_SHAREMEMVIEW_H__BFF33AB7_A398_11D1_887F_D42B07C10710__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

class CShareMemView : public CView
{
protected: // create from serialization only
    CShareMemView();
    DECLARE_DYNCREATE(CShareMemView)

// Attributes
public:
    CShareMemDoc* GetDocument();

// Operations
public:

// Overrides

    // ClassWizard generated virtual function overrides
    //{{AFX_VIRTUAL(CShareMemView)
    public:
    virtual void OnDraw(CDC* pDC);  // overridden to draw this view
    virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
    protected:
    virtual BOOL OnPreparePrinting(CPrintInfo* pInfo);
    virtual void OnBeginPrinting(CDC* pDC, CPrintInfo* pInfo);
    virtual void OnEndPrinting(CDC* pDC, CPrintInfo* pInfo);
    //}}AFX_VIRTUAL

// Implementation
public:
    virtual ~CShareMemView();
#ifdef _DEBUG
    virtual void AssertValid() const;
    virtual void Dump(CDumpContext& dc) const;
#endif

protected:

// Generated message map functions
protected:
    //{{AFX_MSG(CShareMemView)
    afx_msg void OnFileWritememoryfile();
    afx_msg void OnFileReadmemoryfile();
    afx_msg void OnChar(UINT nChar, UINT nRepCnt, UINT nFlags);
    //}}AFX_MSG
    DECLARE_MESSAGE_MAP()
};

#ifndef _DEBUG  // debug version in ShareMemView.cpp
inline CShareMemDoc* CShareMemView::GetDocument()
   { return (CShareMemDoc*)m_pDocument; }
#endif

/////////////////////////////////////////////////////////////////////////////

//{{AFX_INSERT_LOCATION}}

// Microsoft Visual C++ will insert additional declarations immediately
before the previous line.

#endif // !defined(AFX_SHAREMEMVIEW_H__BFF33AB7_A398_11D1_887F_D42B07C10710__INCLUDED_)

// ShareMemView.cpp : implementation of the CShareMemView class
//

#include “stdafx.h”
#include “ShareMem.h”

#include “ShareMemDoc.h”
#include “ShareMemView.h”

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CShareMemView

IMPLEMENT_DYNCREATE(CShareMemView, CView)

BEGIN_MESSAGE_MAP(CShareMemView, CView)
    //{{AFX_MSG_MAP(CShareMemView)
    ON_COMMAND(ID_FILE_WRITEMEMORYFILE, OnFileWritememoryfile)
    ON_COMMAND(ID_FILE_READMEMORYFILE, OnFileReadmemoryfile)
    ON_WM_CHAR()
    //}}AFX_MSG_MAP
    // Standard printing commands
    ON_COMMAND(ID_FILE_PRINT, CView::OnFilePrint)
    ON_COMMAND(ID_FILE_PRINT_DIRECT, CView::OnFilePrint)
    ON_COMMAND(ID_FILE_PRINT_PREVIEW, CView::OnFilePrintPreview)
END_MESSAGE_MAP()


/////////////////////////////////////////////////////////////////////////////
// CShareMemView construction/destruction

CShareMemView::CShareMemView()
{    // TODO: add construction code here

}

CShareMemView::~CShareMemView()
{
}

BOOL CShareMemView::PreCreateWindow(CREATESTRUCT& cs)
{
    // TODO: Modify the Window class or styles here by modifying
    //  the CREATESTRUCT cs

    return CView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// CShareMemView drawing

void CShareMemView::OnDraw(CDC* pDC)
{
    CShareMemDoc* pDoc = GetDocument();
    ASSERT_VALID(pDoc);

    pDC->TextOut(0, 0, pDoc->text);
    // TODO: add draw code for native data here
}

/////////////////////////////////////////////////////////////////////////////
// CShareMemView printing

BOOL CShareMemView::OnPreparePrinting(CPrintInfo* pInfo)
{
    // default preparation
    return DoPreparePrinting(pInfo);

}

void CShareMemView::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
    // TODO: add extra initialization before printing
}

void CShareMemView::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
    // TODO: add cleanup after printing
}

/////////////////////////////////////////////////////////////////////////////
// CShareMemView diagnostics

#ifdef _DEBUG
void CShareMemView::AssertValid() const
{
    CView::AssertValid();
}

void CShareMemView::Dump(CDumpContext& dc) const
{
    CView::Dump(dc);
}

CShareMemDoc* CShareMemView::GetDocument() // non-debug version is inline
{
    ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CShareMemDoc)));
    return (CShareMemDoc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CShareMemView message handlers

void CShareMemView::OnFileWritememoryfile()
{

    CShareMemDoc* pDoc = GetDocument();

    ASSERT_VALID(pDoc);

    HANDLE MemoryMappingHandle;

    MemoryMappingHandle = CreateFileMapping((HANDLE) 0xFFFFFFFF, NULL,
PAGE_READWRITE, 0, 2048, “MemoryFile”);

    LPVOID FilePointer = MapViewOfFile(MemoryMappingHandle, FILE_MAP_WRITE, 0, 0, 0);

    ::lstrcpy((char *) FilePointer, (LPCTSTR) pDoc->text);

    UnmapViewOfFile((LPVOID) FilePointer);

    if(FilePointer != NULL){
        AfxMessageBox(“Memory file written.”);
    }
}

void CShareMemView::OnFileReadmemoryfile()
{

    CShareMemDoc* pDoc = GetDocument();
    ASSERT_VALID(pDoc);

    HANDLE MemoryMappingHandle = NULL;

    MemoryMappingHandle = OpenFileMapping(FILE_MAP_READ, FALSE,
“MemoryFile”);

    LPVOID FilePointer = MapViewOfFile(MemoryMappingHandle, FILE_MAP_READ |
FILE_MAP_WRITE, 0, 0, 0);

    pDoc->text = (char *) FilePointer;

    UnmapViewOfFile((LPVOID) FilePointer);

    CloseHandle(MemoryMappingHandle);

    Invalidate();

}

void CShareMemView::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{
    // TODO: Add your message handler code here and/or call default
    CShareMemDoc* pDoc = GetDocument();
    ASSERT_VALID(pDoc);

    pDoc->text += nChar;

    Invalidate();
    CView::OnChar(nChar, nRepCnt, nFlags);
}

Figure 7.2  Passing data between processes through memory.

What’s Ahead

In the next chapter, we continue with our guided tour of Visual C++ and start working with a very popular topic: connecting to the Internet. We learn to set up a Web browser in Visual C++ and how to use the HTTP and FTP protocols.