MFC 操作EXCEl 循环给每一列的每一项赋值，如果项很多，就出现异常

Question

_Application app;
Workbooks books;
_Workbook book;
Worksheets sheets;
_Worksheet sheet;
Range range;
Font font;
Range cols;  // m_  定义的变量 类型为Cstring
Cstring  m_md5 ="00";  
Cstring m_operators ="1001";
 Cstring   m_auth = "ffffff";
Cstring m_stype ="110";
Cstring m_Identifier = "0";
Cstring m_times ="1030";

CString Prefix ; 
Prefix = m_md5+m_operators+m_auth+m_stype+m_Identifier+m_times;

__int64 nBegin=0;
__int64 nEnd  =0;
__int64 nMax  = 0;
__int64  nTmp ;
sscanf(m_end,"%I64x",&nEnd);
sscanf("ffffffffffff","%I64x",&nMax);
sscanf(m_begin,"%I64x",&nBegin);  COleVariant covOptional((long)DISP_E_PARAMNOTFOUND, VT_ERROR);

if( !app.CreateDispatch("Excel.Application") )
{
this->MessageBox("无法创建Excel应用！");
return;
}
books=app.GetWorkbooks();
book=books.Add(covOptional);
sheets=book.GetSheets();
sheet=sheets.GetItem(COleVariant((short)1));
    
char tt[] = "A1";
char ffff[] = "B1";

range=sheet.GetRange(COleVariant(tt),COleVariant(tt));
range.SetValue2(COleVariant("STD ID"));
font=range.GetFont();
font.SetBold(COleVariant((short)TRUE));

range=sheet.GetRange(COleVariant(ffff),COleVariant(ffff));
range.SetValue2(COleVariant("MAC"));
font=range.GetFont();
font.SetBold(COleVariant((short)TRUE));

char tmp[12] = {0};
char posFisrt[3] = {0};
char posSec[3]  = {0};
int i = 2;
int nTimes = 0;
CString  RealValue ;  // 当  nEnd  大于nTmp的时候， 也就是说要插入很多项时，会出现异常，
for(nTmp = nBegin ; nTmp <= nEnd; nTmp++,i++)
{  
        RealValue.Format(_T(""));

if(!(i%160))
{    nTimes++;
   i = 2;
           AfxMessageBox("xxxx");
} memset(posSec,0,3);
memset(posFisrt,0,3);
        memset(tmp,0,12);
CString  strValue(_i64toa(nTmp,tmp,16));
int StrValueLen  = strValue.GetLength();
if( StrValueLen < 12)
{
for( int i = 0 ; i < 12-StrValueLen ; i++)
{
RealValue +="0";
}

}
RealValue +=strValue;
CString  STD_ID =  Prefix+RealValue;
        
                sprintf(posFisrt,"%c%d",'A'+ 2*nTimes ,i);
sprintf(posSec,"%c%d",'B'+2*nTimes,i);


range=sheet.GetRange(COleVariant(posSec),COleVariant(posSec));

range.SetValue2(COleVariant(RealValue));

range=sheet.GetRange(COleVariant(posFisrt),COleVariant(posFisrt));

    //出现异常的地方
range.SetValue2(COleVariant(STD_ID));


}
cols=range.GetEntireColumn();
cols.AutoFit();

app.SetVisible(TRUE);
app.SetUserControl(TRUE);
}单步调试，异常出现在语句range.SetValue2(COleVariant(STD_ID));
找了一下， 没有找到原因， 还有其他赋值方式没有？