public static void ClearFilter(this GridView gv, string propertyName)
{
var Criteria = gv.GetCriteria() == null ? new List<CriteriaOperator>() : gv.GetCriteria().ToList();
var ActiveCriteria = new GroupOperator(Criteria.ToArray());
if (ReferenceEquals(ActiveCriteria, null)) return;
gv.ClearColumnsFilter();
gv.ActiveFilterCriteria = ActiveCriteria.ClearFilter(propertyName);
gv.ApplyColumnsFilter();
}