COM组件中调用JavaScript函数的实例讲解

[id(2)] HRESULT longCalc([in] DOUBLE v1, [in] DOUBLE v2, [in, optional] VARIANT scriptCallback); 

// 假设回调原型为：  
// scriptCallbackFunc(LONG nCurrentProgress, LONG nTotalProgress, BSTR bstrProgressName); 
// 此方法由JS脚本来实现 
STDMETHODIMP CA:: longCalc (DOUBLE v1, DOUBLE v2, VARIANT scriptCallback) 
{ 
  CComPtr<IDispatch> spCallback; 
  if (scriptCallback.vt == VT_DISPATCH) 
     spCallback = scriptCallback.pdispVal; 
   
 
  // 参数准备 
  CComVariant varResult; 
  CComVariant avarParams[3]; 
  avarParams[0] = “开始计算股票”;    // bstrProgressName 
  avarParams[0].vt = VT_BSTR; 
  avarParams[1] = 100;               // nTotalProgress 
  avarParams[1].vt = VT_I4; 
  avarParams[2] = 0;                 // nCurrentProgress 
  avarParams[2].vt = VT_I4; 
  DISPPARAMS params = { avarParams, NULL, 3, 0 }; 
 
 
  if(spCallback) 
     spCallback->Invoke(0,  
        IID_NULL,  
        LOCALE_USER_DEFAULT,  
        DISPATCH_METHOD,  
        ¶ms, &varResult, NULL, NULL); 
 
  BOOL bFinished = false; 
   
 
  while(!bFinished) 
  { 
     // 计算工作… 
     Sleep(1000); 
     v1 = v1+v2; 
  
    // 回调客户 
    if(spCallback) 
    { 
      avarParams[0] = “正在计算股票…”; 
      avarParams[2] = 0; 
      spCallback->Invoke(0,  
             IID_NULL,  
             LOCALE_USER_DEFAULT,  
             DISPATCH_METHOD,  
             ¶ms, &varResult, NULL, NULL); 
     } 
 
     if(…) 
         bFinished = TRUE; 
   } // while OK! 
 
   return S_OK; 
} 

<script language="javascript"> 
<!-- 
   // 符合回调原型：scriptCallbackFunc 
   function scfDisplayProgress(nCurrentProgress, nTotalProgress, bstrProgressName) 
   { 
       window.status = bstrProgressName + “:”+(nCurrentProgress *100/TotalProgress); 
   } 
  
   // 创建组件并执行longCalc 
   var objA = new ActiveXObject(“MyCom.A”); 
 
    // 使用回调: 执行时在IE状态栏显示进度 
    objA. longCalc (100, 200, scfDisplayProgress);  
 
    // 不使用回调 
    objA. longCalc (100, 200);  
//--> 
</script>