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把javascript,vbscript中得数组传递给COM组件（or Activex）

摘要: 把javascript,vbscript中得数组传递给COM组件（or Activex）

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COM组件的方法在IDL中的声明：
[id(1), helpstring("方法InputArray")] HRESULT InputArray([in] VARIANT vData);

在脚本中建立数组并调用COM组件的方法：
当数组很大的时候，like 100k ,javascript在给数组赋值的时候效率非常低！完成时间，cpu占用率，占用的内存都大的可怕。反而VBScript却完成的很好。

?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

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

COM组件的代码：
从代码中可以看到vbscript传进来的是个SafeArray。而javascript的情况就复杂了，javascript中得数组并不是真正意义上的数组，这个“数组”传到COM中被放进一个集合里，参数VARIANT的类型被置为VT_DISPATCH，我们得通过这个IDispatch指针调用invoke才能得到用来读取集合的枚举接口。
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 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;
}