使用WM_COPYDATA实现进程间通信

发送端

LRESULT copyData;  //copyDataResult has value returned by other app 
CWnd *pOtherWnd = CWnd::FindWindow(NULL, _T("窗体名"));
CString strData;
strData.Format(L"%.1lf", tickdata);
if (pOtherWnd)
{
	COPYDATASTRUCT cpd;   //上面提到的结构体
	cpd.dwData = 0;
	cpd.cbData = strData.GetLength() + sizeof(wchar_t);        //sizeof(wchar_t)指 \0 的长度。     
	cpd.lpData = (void*)strData.GetBuffer(cpd.cbData);
	copyData = pOtherWnd->SendMessage(WM_COPYDATA, (WPARAM)AfxGetApp()->m_pMainWnd->GetSafeHwnd(), (LPARAM)&cpd);
	strData.ReleaseBuffer();
}

接收端
接收端打开发送端程序并隐藏界面

ShellExecute(this->m_hWnd, _T("open"), _T("send.exe"), NULL, NULL, SW_HIDE);

接收端接收并显示数据—右键项目->类向导->消息->添加WM_COPYDATA处理程序

BOOL CTestDlg::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	
	CString strRec = (LPCTSTR)(pCopyDataStruct->lpData);
	strRec += _T("  mm");
	SetDlgItemText(IDC_STATIC_SHOWTICK, strRec);
    
    //局部刷新数据
	CRect rc;
	m_staticshowtick.GetWindowRect(rc);
	ScreenToClient(rc);
	InvalidateRect(rc);

	return CDialogEx::OnCopyData(pWnd, pCopyDataStruct);
}