Advanced MFC Programming

Chapter 13. Adding Special Features to Application
……
}
m_hMapFile=::CreateFileMapping
(
(HANDLE)0xFFFFFFFF,
NULL,
PAGE_READWRITE,
0,
BUFFER_SIZE,
MAPPING_PROJECT
);
Here, BUFFER_SIZE is a macro defined as an integer in header file “Common.h”. Also,
MAPPING_PROJECT is a macro defined as a string. They will be used by both “Sender” and “MsgRcv”. In
message handler CSenderDlg::OnButtonSend(), before the message is sent out, we obtain the text from the
edit box, create a view of file and put the text into the buffers. Then message MSG_SENDSTRING is sent to
“MsgRcv”:
void CSenderDlg::OnButtonSend()
{
CWnd *pWnd;
LPSTR lpMapAddress;
UpdateData(TRUE);
lpMapAddress=(LPSTR)MapViewOfFile
(
m_hMapFile,
FILE_MAP_ALL_ACCESS,
0,
0,
0
);
}
if(lpMapAddress != NULL)
{
memcpy(lpMapAddress, m_szText, max(m_szText.GetLength(), BUFFER_SIZE));
}
pWnd=CWnd::FindWindow(CLASS_NAME_RECIEVER, NULL);
if(pWnd != NULL && ::IsWindow(pWnd->m_hWnd))
{
pWnd->PostMessage(g_uMsgSendStr, (WPARAM)GetSafeHwnd(), (LPARAM)NULL);
}
In project “MsgRcv”, the client window is implemented using edit view instead of original list view,
this makes it easier for us to display text. After receiving the message, we open the file mapping object,
create a view of file, then retrieve text from the buffers. Then we access the edit view, select all the text
contained in the view, and replace the selected text with the newly obtained text. Finally, the acknowledge
message is sent back:
LONG CMainFrame::OnSendStr(UINT wParam, LONG lParam)
{
CWnd *pWnd;
CString szText;
HANDLE hMapFile;
LPSTR lpMapAddress;
pWnd=CWnd::FromHandle((HWND)wParam);
ASSERT(pWnd != NULL);
pWnd->PostMessage(g_uMsgReceived);
hMapFile=::OpenFileMapping
(
FILE_MAP_ALL_ACCESS,
FALSE,
425