private int AddNumericGroupItems(ExcelPivotTableFieldNumericGroup group, double start, double end, double interval)
{
if (interval < 0)
{
throw (new Exception("The interval must be a positiv"));
}
if (start > end)
{
throw(new Exception("Then End number must be larger than the Start number"));
}
XmlElement groupItems = group.TopNode.SelectSingleNode("d:fieldGroup/d:groupItems", group.NameSpaceManager) as XmlElement;
int items = 2;
//First date
double index=start;
double nextIndex=start+interval;
AddGroupItem(groupItems, "<" + start.ToString(CultureInfo.InvariantCulture));
while (index < end)
{
AddGroupItem(groupItems, string.Format("{0}-{1}", index.ToString(CultureInfo.InvariantCulture), nextIndex.ToString(CultureInfo.InvariantCulture)));
index=nextIndex;
nextIndex+=interval;
items++;
}
AddGroupItem(groupItems, ">" + nextIndex.ToString(CultureInfo.InvariantCulture));
return items;
}