public override object Apply(object leftvalue, object rightvalue)
{
if (leftvalue is int)
if (rightvalue is int)
return (int)leftvalue * (int)rightvalue;
else
return (int)leftvalue * (double)rightvalue;
else if (rightvalue is int)
return (double)leftvalue * (int)rightvalue;
else
return (double)leftvalue * (double)rightvalue;
}