d179.bmp.txt

Visual C++通信编程实例

OPCCallback0 {; J
virtual ~OPCCallbackO{;J
//COM映射，将接口IOPCDataCallback与实现类结合在一起
BEGIN_COM_MAP(OPCCallback)
  COM_INTERFACE_ENTRY(IOPCDataC allb ack)
END_COM_MAPO
DECLARE_NOT_AGGREGATABLE(OPCCallback)//不允许被外部对象聚合
／／下面四个函数都是来自IOPCDataCallback的纯虚函数，函数中可加上PostMessage来通知接收
数据的视图。
  STDMETHODIMP OnDataChange(
  DWORDTransid,
  OPCHANDLEgrphandle,
  HRESULT    masterquality,
  HRESULT mastererror,
  DWORD    count,
  OPCHANDLE 4 clienthandles,
  VARIANT    冰values,
  WORD    4quality,
  FILETIME *time,
  HRESULT  *errors);／／数据变化时，自动执行此函数。
STDMETHODIMP OnReadComplete(
DWORD     Transid,
OPCHANDLE  grphandle,
HRESULT   masterquality,
HRESULT   mastererror,
DWORD     count
  OPCHANDLE * clienthandles,
 VARIANT     * values,
 WORD          * quality,
FILETIME *time,
  HRESULT      * errors);，，调用 IOCPAsyncI02::Read后,自动执行。
STDMETHODIMP OnWriteComplete(
DWORD Transid,
OPCHANDLE grphandle,
HRESULT    mastererr,
 DWORD    count,
OPCHANDLE+ clienthandles,
HRESULT  4 errors);，／调用IOCPAsyncI02::Write后，自动执行。
STDMETHODIMP OnCancelComplete(
DWORDtransid,
OPCHANDLE grphandle);，／调用IOCPAsyncI02::Cancel后，自动执行。
/79