1）Pass each structure member as an individual method parameter. 
2）Serialize the structure to an opaque array of bytes. 
3）Serialize the structure to an array of VARIANTs, one array element per structure member.
4）Implement a dispatch/dual wrapper object that contains the structure and pass an interface to the wrapper object as a parameter.

1 就是依次返回每个结构体成员
2 序列化
3 序列化到VARIANT类型里面
4 多写一个对象,包装这个结构体.

variant与结构体之间的相互转化方式

用SafeArray传。下面是代码：

struct studentsInfo

{

short grade;

CString name;

int type;

};

VARIANT CMyIeDlg::SetStruct()
{
HRESULT hr;
SAFEARRAY* pSa = NULL;
SAFEARRAYBOUND rgbounds;

VARIANT vaResult;

VariantInit(&vaResult);

rgbounds.1Lbound = 0;//下标从0开始

rgbounds.cElements = 1;//元素个数为1个结构体
studentsInfo StudentStruct;

StudentStruct = stuctInfo;//结构体复制

pSa = SafeArrayCreate(VT_VARIANT, 1, &rgbounds);

pSa->fFeatures = FADF_AUTO | FADF_FIXEDSIZE;//指定在栈上分配数据，大小不可以改变

pSa->cbElements = sizeof(StudentStruct);

pSa->pvData = &StudentStruct;

vaResult.vt = VT_ARRAY | VT_UI1;

vaResult.parray = pSa;

return vaResult;

}

void CMyIeDlg::GetStruct()
{
HRESULT hr;
SAFEARRAY* psaStudent = NULL;
studentsInfo *pStudentStruct = NULL;
studentsInfo students;

psaStudent = SetStruct();

hr = SafeArrayAccessData(psaStudent, reinterpret_cast<PVOID*>(&pStudentStruct));

students = *pStudentStruct;

hr = SafeArrayUnaccessData(psaStudent);

SafeArrayDestroy(psaStudent);

}