在CC边界上传递CComSafeArray

时间:2013-07-15 22:31:50

标签: c++ memory com atl

我正在努力(i)在COM边界获得一个longs的安全阵列,以及(ii)为方便起见使用CComSafeArray。

我的问题是,在设置COM属性后,我遇到了不可预测的崩溃(请参阅下面的 pPrologue-> EligibleProducts = var; )。我发现很难理解如何使用Microsoft文档中的CComSafeArray,任何人都可以解决这个问题吗?提前谢谢!

在IDL中我有:

[propget, id(1), helpstring("property EligibleProducts")] HRESULT EligibleProducts([out, retval] VARIANT* pVal);
[propput, id(1), helpstring("property EligibleProducts")] HRESULT EligibleProducts([in] VARIANT newVal);

我的服务器代码是:

STDMETHODIMP CPrologue::put_EligibleProducts(VARIANT newVal)
{
    HRESULT hr = E_FAIL;

    AFX_MANAGE_STATE(AfxGetStaticModuleState())

    //start by clearing out any existing data
    m_EligibleProducts.clear();

    if(newVal.vt | (VT_ARRAY & VT_I4))
    {
        //construct a wrapper class with the passed in SAFEARRAY
         CComSafeArray<long> wrapper;
         wrapper.Attach(newVal.parray);

         int iProductID = 0;

         //loop through products and add them to our vector
         int iCount = wrapper.GetCount();
         for(int iIndex = 0; iIndex < iCount; iIndex++)
         {
             iProductID = wrapper.GetAt(iIndex);
             if(iProductID > 0)
             {
                 m_EligibleProducts.push_back(iProductID);
             }
         }

         hr = S_OK;

    return hr;
}

我的主叫代码是:

                VARIANT var;
                ::VariantInit(&var);
                var.vt = VT_ARRAY | VT_I4;

                CComSafeArray<long> wrapper;

                for(std::vector<long>::const_iterator it = products.begin(); it != products.end(); it++)
                {
                    wrapper.Add(*it);
                }

                //get the SAFEARRAY from the wrapper
                var.parray = wrapper.Detach();

                //and store it on the appropriate business object
                IProloguePtr pPrologue = pCustomer->Prologue;    
                **pPrologue->EligibleProducts = var;**

                //clean up the variant (and hence SAFEARRAY)
                ::VariantClear(&var);

1 个答案:

答案 0 :(得分:3)

  

if(newVal.vt |(VT_ARRAY&amp; VT_I4))

这不符合你的想象。这种情况总是如此。您正在寻找if (newVal.vt == VT_ARRAY | VT_I4)

put_EligibleProducts中,您有Attach个CComSafeArray指向VARIANT内的指针,但您尚未分离它。当wrapper超出范围时,它会破坏安全阵列。然后呼叫者尝试通过VariantClear第二次销毁它。这是你遇到困难的直接原因。

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