DataTable dt = new DataTable();
foreach (string col in listItems)
dt.Columns.Add(col, typeof(string));
FilteredElementCollector ids = new FilteredElementCollector(selectedSchedule.Document, selectedSchedule.Id);
var elementIds = ids.WhereElementIsNotElementType().ToElementIds();
List<string> data = new List<string>();
foreach (ElementId elementId in elementIds) {
Element element = doc.GetElement(elementId);
foreach (string stringParameter in parameters) {
Parameter parameter = element.LookupParameter(stringParameter);
if (null != parameter)
data.Add(element.LookupParameter(stringParameter).AsValueString());
}
dt.Rows.Add(data.ToArray());
data.Clear();
}