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

王朝vc·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

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。

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;

}

 
 
 
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