c++ - 遍历BSTR的VARIANT/SAFEARRAY以分配值并在C++中打印到控制台

我试图用值“test”填充BSTR类型的10个索引的SAFEARRAY，并在分配SAFEARRAY的每个索引以验证其正确性后打印出控制台的值。我运行了调试器，并在下面的前5个索引中获得了这些值(我的SAFEARRAY称为sa)。我以某种方式错误地迭代了SAFEARRAY或使用了错误的类型，每个索引都应该是“test”。关于我做错什么的任何建议吗？

sa[0] = "test"
sa[1] = "est"
sa[2] = "st"
sa[3] = "t"
sa[4] = ""

....

#include <iostream>
#include <string>
#include <Windows.h>
#include <atlbase.h>
#include <comutil.h>
#include <string.h>
#include <stdio.h>

using namespace std;

void fillVariant(VARIANT& varIn, BSTR &srcArray);

int main()
{

    BSTR *theArray = new BSTR[10];
    for(int i = 0 ; i < 10; i++)
    {

        theArray[i] = SysAllocString(L"test");
    }

    VARIANT variantArray;
    fillVariant(variantArray, *theArray);


    return 0;
}

void fillVariant(VARIANT& varIn, BSTR &srcArray)
{
    VARIANT *variantArray = &varIn;
    VariantInit(variantArray);
    variantArray->vt = VT_ARRAY|VT_BSTR;

    SAFEARRAY* sa;
    SAFEARRAYBOUND aDim[1];
    aDim[0].lLbound = 0;
    aDim[0].cElements = 10;

    sa = SafeArrayCreate(VT_BSTR, 1, aDim);

    BSTR* dwArray = NULL;
    SafeArrayAccessData(sa, (void**)&dwArray);

    for(int i = 0; i < 10; i++)
    {
        dwArray[i] = &srcArray[i];

        BSTR tmp = (BSTR) dwArray[i];
        std::wstring ws(tmp);
        //std::wstring ws(*dwArray[i], SysStringLen(dwArray[i]));
        std::wcout << ws << endl;

    }
    SafeArrayUnaccessData(sa);
    variantArray->parray = sa;
}

最佳答案

您没有正确填写VARIANT。尝试以下方法:

#include <iostream>
#include <string>
#include <Windows.h>
#include <atlbase.h>
#include <comutil.h>
#include <string.h>
#include <stdio.h>

using namespace std;

void fillVariant(VARIANT& varIn, BSTR *srcArray, int srcArrayLen);

int main()
{
    BSTR *theArray = new BSTR[10];
    for(int i = 0 ; i < 10; i++)
    {
        theArray[i] = SysAllocString(L"test");
    }

    VARIANT variantArray;
    fillVariant(variantArray, theArray, 10);

    // don't forget to free memory when done!
    // note: the VARIANT owns the BSTRs, so DON'T free them!
    VariantClear(&variantArray);
    delete[] theArray;

    return 0;
}

void fillVariant(VARIANT& varIn, BSTR *srcArray, int srcArrayLen)
{
    VARIANT *variantArray = &varIn;
    VariantInit(variantArray);

    SAFEARRAYBOUND aDim[1];
    aDim[0].lLbound = 0;
    aDim[0].cElements = srcArrayLen;

    SAFEARRAY* sa = SafeArrayCreate(VT_BSTR, 1, aDim);
    if (sa)
    {
        BSTR* dwArray = NULL;
        SafeArrayAccessData(sa, (void**)&dwArray);

        for(int i = 0; i < srcArrayLen; i++)
        {
            // note: passing ownership, NOT making a copy
            dwArray[i] = srcArray[i];

            //std::wstring ws(dwArray[i], SysStringLen(dwArray[i]));
            std::wcout << dwArray[i] << endl;
        }

        SafeArrayUnaccessData(sa);

        variantArray->vt = VT_ARRAY|VT_BSTR;
        variantArray->parray = sa;
    }
}

或者:

#include <iostream>
#include <string>
#include <Windows.h>
#include <atlbase.h>
#include <comutil.h>
#include <string.h>
#include <stdio.h>

using namespace std;

void fillVariant(VARIANT& varIn, BSTR *srcArray, int srcArrayLen);

int main()
{
    BSTR *theArray = new BSTR[10];
    for(int i = 0 ; i < 10; i++)
    {
        theArray[i] = SysAllocString(L"test");
    }

    VARIANT variantArray;
    fillVariant(variantArray, theArray, 10);

    // don't forget to free memory when done!

    VariantClear(&variantArray);

    // note: the VARIANT DOES NOT own the BSTRs, so DO free them!
    for(int i = 0 ; i < 10; i++)
    {
        SysFreeString(theArray[i]);
    }
    delete[] theArray;

    return 0;
}

void fillVariant(VARIANT& varIn, BSTR *srcArray, int srcArrayLen)
{
    VARIANT *variantArray = &varIn;
    VariantInit(variantArray);

    SAFEARRAYBOUND aDim[1];
    aDim[0].lLbound = 0;
    aDim[0].cElements = srcArrayLen;

    SAFEARRAY* sa = SafeArrayCreate(VT_BSTR, 1, aDim);
    if (sa)
    {
        for(LONG i = 0; i < srcArrayLen; i++)
        {
            // note: makes a copy, DOES NOT pass ownership!
            SafeArrayPutElement(sa, &i, srcArray[i]);

            //std::wstring ws(srcArray[i], SysStringLen(srcArray[i]));
            std::wcout << srcArray[i] << endl;
        }

        variantArray->vt = VT_ARRAY|VT_BSTR;
        variantArray->parray = sa;
    }
}

关于c++ - 遍历BSTR的VARIANT/SAFEARRAY以分配值并在C++中打印到控制台，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/25004408/