Linq Distinct

  var t = (from orders in replenismentOrders
                     where
                     (string .IsNullOrEmpty (conditDTO .OrderId) || orders .ID  ==conditDTO .OrderId)
                     &&(string .IsNullOrEmpty (conditDTO .RVC )|| orders .RVC .ID ==conditDTO .RVC)
                     &&(string .IsNullOrEmpty (conditDTO .OrderStatus.ToString())|| orders .ReplenishOrderStatus==conditDTO .OrderStatus )
                     select orders).Distinct();