CCWGraph::PlotY()该如何调用

[xuyongsky]

我想调用这个函数（NI的GRAPH控件，用以给制各种图像，如（正弦波，方波等）），可是总是说类型不匹配，查看了VARIANT，也不知道该如何转换。
void CCWGraph::PlotY(const VARIANT& YData, const VARIANT& xFirst, const VARIANT& xInc, const VARIANT& bPlotPerRow)
{
static BYTE parms[] =
VTS_VARIANT VTS_VARIANT VTS_VARIANT VTS_VARIANT;
InvokeHelper(0xd, DISPATCH_METHOD, VT_EMPTY, NULL, parms,
&YData, &xFirst, &xInc, &bPlotPerRow);
}

以下是对它的定义。
struct tagVARIANT;
typedef tagVARIANT VARIANT;

struct tagVARIANT
{
union
{
struct __tagVARIANT
{
VARTYPE vt;
WORD wReserved1;
WORD wReserved2;
WORD wReserved3;
union
{
LONG lVal;
BYTE bVal;
SHORT iVal;
FLOAT fltVal;
DOUBLE dblVal;
VARIANT_BOOL boolVal;
_VARIANT_BOOL bool;
SCODE scode;
CY cyVal;
DATE date;
BSTR bstrVal;
IUnknown __RPC_FAR *punkVal;
IDispatch __RPC_FAR *pdispVal;
SAFEARRAY __RPC_FAR *parray;
BYTE __RPC_FAR *pbVal;
SHORT __RPC_FAR *piVal;
LONG __RPC_FAR *plVal;
FLOAT __RPC_FAR *pfltVal;
DOUBLE __RPC_FAR *pdblVal;
VARIANT_BOOL __RPC_FAR *pboolVal;
_VARIANT_BOOL __RPC_FAR *pbool;
SCODE __RPC_FAR *pscode;
CY __RPC_FAR *pcyVal;
DATE __RPC_FAR *pdate;
BSTR __RPC_FAR *pbstrVal;
IUnknown __RPC_FAR *__RPC_FAR *ppunkVal;
IDispatch __RPC_FAR *__RPC_FAR *ppdispVal;
SAFEARRAY __RPC_FAR *__RPC_FAR *pparray;
VARIANT __RPC_FAR *pvarVal;
PVOID byref;
CHAR cVal;
USHORT uiVal;
ULONG ulVal;
INT intVal;
UINT uintVal;
DECIMAL __RPC_FAR *pdecVal;
CHAR __RPC_FAR *pcVal;
USHORT __RPC_FAR *puiVal;
ULONG __RPC_FAR *pulVal;
INT __RPC_FAR *pintVal;
UINT __RPC_FAR *puintVal;
struct __tagBRECORD
{
PVOID pvRecord;
IRecordInfo __RPC_FAR *pRecInfo;
} __VARIANT_NAME_4;
} __VARIANT_NAME_3;
} __VARIANT_NAME_2;
DECIMAL decVal;
} __VARIANT_NAME_1;
};
我该如何调用它???

[try876]

比如你要传入参数a
用这样就行啦COleVariant(a)

[try876]

VARIANT是一个结构,可以兼容各种类型