只能使用可选参数进行查询

Question

I currently have the following method:

        public List<Order> GetOrders(int profileId, string timeSpan, string workOrd, string partNo, bool includeDeleted)
    {
        DateTime startDate = DateTime.Now;
        DateTime endDate = DateTime.Now;
        string[] times = (!string.IsNullOrWhiteSpace(timeSpan)) ? timeSpan.Trim().Split('-') : new string[] { "", "" };
        if (!string.IsNullOrWhiteSpace(times[0]) && !string.IsNullOrWhiteSpace(times[0]))
        {
            startDate = DateTime.Parse(times[0]).Date;
            endDate = DateTime.Parse(times[1]).Date;
        }

        //New Real Query
        IQueryable<Order_Travel> otQuery = _context.Order_Travels.Where(x =>
            (profileId != 0 || x.Profile.ProfileID == profileId)
            && ((timeSpan == null || timeSpan.Trim() == "") || ((DbFunctions.TruncateTime(x.TimeRecieved) >= startDate) 
                                                            && (DbFunctions.TruncateTime(x.TimeRecieved) <= endDate)))
            && ((workOrd == null || workOrd.Trim() == "") || x.Order.WorkOrdNo == workOrd)
            && ((partNo == null ||partNo.Trim() == "") || x.Order.PartNo == partNo)
            && (!includeDeleted || x.Aborted == true));

        //The results is now in order_travel. Under here binding them to a list of orders with only the respective orderTravels included.
        List<Order> orders = new List<Order>();
        List<Order_Travel> ots = otQuery.ToList();
        foreach (Order_Travel ot in ots)
        {
            var OrderInList = orders.FirstOrDefault(X => X == ot.Order);
            if (OrderInList == null)
            {
                orders.Add(ot.Order);
                OrderInList = orders.FirstOrDefault(X => X == ot.Order);
                OrderInList.OrderTravels.Clear();
                OrderInList.OrderTravels.Add(ot);
            }
            else
            {
                OrderInList.OrderTravels.Add(ot);
            }
        }
        return orders;
    }

What I need it to do, is (as I've attempted) to make a call, finding all Order_Travel objects that match the paramters sent to it. If some (or all) are left blank, it takes everything, regardless of the values. The code right now, does not return anything, if a blank search is made (a search that does not have any parameters), and I can not see what could be the issue. I have tried debugging it, but with no luck.

Any help would be greatly appreciated!

Thanks!

Answer 1

Filter one option at a time, instead of trying to put everything into a single expression:

IQueryable<T> query = all;    // start with everything

if (IsPresent(option1))
{
   query = query.Where(t => t.XXX == option1);   
}

Example

IQueryable<Order_Travel> otQuery = _context.Order_Travels;

if (profileId != 0)
{
    otQuery = otQuery.Where(x => x.Profile.ProfileID == profileId);
}

if (timeSpan != null && timeSpan.Trim() != "")
{
    otQuery = otQuery.Where(x => DbFunctions.TruncateTime(x.TimeRecieved) >= startDate &&
                                 DbFunctions.TruncateTime(x.TimeRecieved) <= endDate);
}

You will also find this easier to maintain than one huge expression.

Answer 2

Probably this part is your problem:

(profileId != 0 || x.Profile.ProfileID == profileId)

It should be

(profileId == 0 || x.Profile.ProfileID == profileId)

If your profile ID is 0, it will only find entries with x.Profile.ProfileID being 0 . Probably there are no such entries.