内存映射实现进程间通信

示例通过内存映射实现从服务器加载bmp位图到内存，客户端从内存读取并显示。

//服务器部分代码void CServerDlg::OnCreateFileMap() {// TODO: Add your control notification handler code hereCButton* pButton = (CButton*)GetDlgItem(IDC_BUTTON1);pButton->EnableWindow(false);CString filename = _T("image\\3.bmp");//1.加载文件m_hFile = CreateFile(filename,GENERIC_READ,FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);if (m_hFile == INVALID_HANDLE_VALUE){MessageBox(_T("文件加载失败!!!"),NULL,MB_OK);return;}m_hMap = CreateFileMapping(m_hFile, NULL, PAGE_READONLY, NULL, NULL, _T("myjpg"));//2.映射整个文件到m_pBaseMapFile = MapViewOfFile(m_hMap,FILE_MAP_READ,0,0,0);}void CServerDlg::OnCloseFileMap() {// TODO: Add your control notification handler code hereCButton* pButton = (CButton*)GetDlgItem(IDC_BUTTON2);pButton->EnableWindow(false);if (m_pBaseMapFile){UnmapViewOfFile(m_pBaseMapFile);}if (m_hMap){CloseHandle(m_hMap);}if (m_hFile){CloseHandle(m_hFile);}}

//客户端部分代码void CClientView::OnOpenFileMap() {// TODO: Add your command handler code herem_hMapFile =OpenFileMapping(FILE_MAP_READ, FALSE,_T("myjpg"));if(m_hMapFile == NULL){MessageBox(_T("文件映射打开失败！"));return;}m_pBaseMapFile=MapViewOfFile(m_hMapFile, FILE_MAP_READ, 0,0,0);SetBitsToBmp((BYTE*)m_pBaseMapFile);}void CClientView::OnCloseFileMap() {// TODO: Add your command handler code hereif (m_pBaseMapFile) { UnmapViewOfFile(m_pBaseMapFile);  }if(m_hMapFile){CloseHandle(m_hMapFile);}}void CClientView::SetBitsToBmp(LPBYTE lpBase){BITMAPFILEHEADER *pFileHeader; // bitmap file-headerBITMAPINFO *pInfoHeader; // bitmap info-headerpFileHeader = (BITMAPFILEHEADER*)lpBase;if(pFileHeader->bfType != MAKEWORD('B', 'M')){ MessageBox(_T("本程序仅读取BMP 文件！"));::UnmapViewOfFile(lpBase);::CloseHandle(m_hMapFile);return;}BYTE *pBits = (BYTE*)lpBase + pFileHeader->bfOffBits;pInfoHeader = (BITMAPINFO*)((BYTE*)lpBase + sizeof(BITMAPFILEHEADER));m_nHeight = pInfoHeader->bmiHeader.biHeight;m_nWidth = pInfoHeader->bmiHeader.biWidth;CClientDC dc(this);// 创建一个与指定DC 兼容的未初始化的位图，选入到内存兼容DC 中m_hMemDC = CreateCompatibleDC(dc);HBITMAP hBitmap = ::CreateCompatibleBitmap(dc, m_nWidth, m_nHeight);::SelectObject(m_hMemDC, hBitmap);//1.正常显示SetDIBitsToDevice(m_hMemDC,0, 0, m_nWidth,m_nHeight,0, 0,0, m_nHeight, pBits, pInfoHeader,DIB_RGB_COLORS); //2.缩放模式/*RECT rc;GetClientRect(&rc);int nWidth = rc.right - rc.left;int nHeight = rc.bottom - rc.top;StretchDIBits(m_hMemDC, 0, 0, nWidth, nHeight, 0, 0, m_nWidth, m_nHeight, pBits, pInfoHeader,DIB_RGB_COLORS,SRCCOPY);*/InvalidateRect(NULL, TRUE);::DeleteObject(hBitmap);}

void CClientView::OnDraw(CDC* pDC){CClientDoc* pDoc = GetDocument();ASSERT_VALID(pDoc);// TODO: add draw code for native data hereBitBlt(pDC->m_hDC,0, 0, m_nWidth, m_nHeight, m_hMemDC,0,0,SRCCOPY);}