把javascript,vbscript中得數組傳遞給COM組件（or Activex）

最後更新：2018-12-04 來源：互聯網

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COM組件的方法在IDL中的聲明：
[id(1), helpstring("方法InputArray")] HRESULT InputArray([in] VARIANT vData);

在指令碼中建立數組並調用COM組件的方法：
當數組很大的時候，like 100k ,javascript在給數組賦值的時候效率非常低！完成時間，cpu佔用率，佔用的記憶體都大的可怕。反而VBScript卻完成的很好。
測試頁面：
<HTML>
<HEAD>
  <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=gb2312">
  <TITLE>對象 BigParamCtl 的 ATL 7.0 測試頁</TITLE>
</HEAD>
<BODY>
  <OBJECT id="BigParamCtl" data="data:application/x-oleobject;base64,G2I3cgi4DEazi5wM0glIGRAHAADYEwAA2BMAAA=="
   classid="CLSID:7237621B-B808-460C-B38B-9C0CD2094819" >
  </OBJECT>
  <SCRIPT LANGUAGE="VBScript">
   Sub InputArray_VBScript

    On Error Resume Next
    Set BigParamCtla = CreateObject("BigParam.BigParamCtl")
    if err<>0 then
     Alert("BigParam not properly installed on this PC!")
    else
     Dim i

     Dim a(10)

     For i = 0 To 10
      a(i) = asc("0")
     Next
     MsgBox("vbscript complete")
     BigParamCtla.InputArray a

           end if

   End Sub
  </SCRIPT>
  <SCRIPT language="javascript">

   function InputArray_javascript()
   {
    var a = new Array(10);
    for(var i = 0; i < 10; i++)
    {
     a[i] = 49 ;
    }
    alert("javascript complete");
    BigParamCtl.InputArray(a);
   }



  </SCRIPT>
  <form name="form1" method="post" action="" ID="Form1">
   <p>
    Ret <input type="text" name="Ret" value="" ID="Text1"> <input type="button" name="Button" value="InputArray_VBScript" onclick="InputArray_VBScript"
     ID="Button1">
   </p>
   <p>
    Ret <input type="text" name="Ret" value="" ID="Text2"> <input type="button" name="Button" value="InputArray_javascript" onclick="InputArray_javascript"
     ID="Button2">
   </p>
  </form>
</BODY>
</HTML>

COM組件的代碼：
從代碼中可以看到vbscript傳進來的是個SafeArray。而javascript的情況就複雜了，javascript中得數組並不是真正意義上的數組，這個“數組”傳到COM中被放進一個集合裡，參數VARIANT的類型被置為VT_DISPATCH，我們得通過這個IDispatch指標調用invoke才能得到用來讀取集合的枚舉介面。
STDMETHODIMP CBigParamCtl::InputArray(VARIANT vData)
{
LPBYTE p ;

DWORD nLen;

HRESULT hr;

if( vData.vt == VT_DISPATCH)
{
  //deal with javascript array
  hr = VariantEnumToBytes(vData.pdispVal,&p, &nLen);
}
else
{
  //deal with vbscript array
  hr = VariantArrayToBytes(&vData, &p, &nLen) ;
}

if( S_OK == hr)
{
//....... do sth on p
delete[] p;
}

return S_OK;
}

HRESULT VariantEnumToBytes(IDispatch* disp, LPBYTE *ppBytes, DWORD *pdwBytes)
{
// DebugBreak();
HRESULT hr;
DISPPARAMS noArgs = { NULL, NULL, 0, 0 };
CComVariant resultV;
hr = disp->Invoke( DISPID_NEWENUM,
  IID_NULL,
  LOCALE_SYSTEM_DEFAULT,
  DISPATCH_PROPERTYGET,
  &noArgs,
  &resultV,
  NULL,
  NULL );
if( FAILED( hr ) && FAILED( resultV.ChangeType( VT_UNKNOWN ) ) )
  return E_FAIL;
// Bug 37459, above Invoke succeeds, but returns resultV.vt == VT_EMPTY, resultV->other param unchanged
if (resultV.vt != VT_UNKNOWN && resultV.vt != VT_DISPATCH)
{
  return E_FAIL;
}

CComQIPtr<IEnumVARIANT> pEnum( resultV.punkVal );
if( !pEnum )
  return E_FAIL;
// Count the elements
*pdwBytes = 0;
hr = S_OK;

//Get Enum Size
while( hr == S_OK )
{
  hr = pEnum->Skip(1);
  if( hr == S_OK )
   (*pdwBytes)++;
}

//allocate memory
*ppBytes = (LPBYTE)new BYTE[*pdwBytes];

int nCount = 0;
CComVariant elemV;
pEnum->Reset();
hr = S_OK;
while( hr == S_OK )
{
  // Could switch to use Skip when Cary gets
  // it working.
  hr = pEnum->Next( 1, &elemV, NULL );
  if( elemV.vt != VT_I4 )
   hr = S_FALSE; // correct for dispproxy bug 19307
  else
  {
   int nTmp = elemV.lVal;
   (*ppBytes)[nCount] = (BYTE)nTmp;
  }

  if( hr == S_OK )
   nCount++;
}

return S_OK;
}

HRESULT VariantArrayToBytes(VARIANT *pVariant, LPBYTE *ppBytes, DWORD *pdwBytes)
{
USES_CONVERSION;
if (pVariant->vt != (VT_VARIANT | VT_BYREF))
return E_INVALIDARG;

if (!(pVariant->pvarVal->vt & VT_ARRAY))
return E_INVALIDARG;

SAFEARRAY* pX = NULL;

if (pVariant->pvarVal->vt & VT_BYREF)
pX = *(pVariant->pvarVal->pparray);
else
pX = pVariant->pvarVal->parray;

if (::SafeArrayGetDim(pX) != 1)
return E_INVALIDARG;

*ppBytes = NULL;
*pdwBytes = 0;

VARIANT *pArray = NULL;
HRESULT hr = E_FAIL;

_variant_t v;
hr = SafeArrayAccessData(pX, (void **) &pArray );
if( SUCCEEDED(hr))
{
*pdwBytes = pX->rgsabound->cElements;
*ppBytes = (LPBYTE)new BYTE[*pdwBytes];

  for( DWORD i = 0; i < *pdwBytes; i++)
  {
   v = pArray[i];
   v.ChangeType(VT_UI1);
   (*ppBytes)[i] = v.bVal;
  }

SafeArrayUnaccessData( pX );
}
else
return hr;

SafeArrayDestroy(pX);

return S_OK;
}

本文章原先以中文撰寫並發佈於 aliyun.com，亦設英文版本，僅作資訊用途。本網站不對文章的準確性，完整性或可靠性或其任何翻譯作出任何明示或暗示的陳述或保證。如對該文章有任何疑慮或投訴，請傳送電郵至 info-contact@alibabacloud.com 並提供相關疑慮或投訴的詳細說明。職員會於 5 個工作天內與您聯絡，一經驗證之後，即會刪除該侵權內容。

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