Question

in my DB, I have e.g. 13 orders.

The code below returns all of them, if the OrderID = 0 and CustomerName = "lorem".

If I comment the line (OrderID == 0) ?.... it works fine. What’s wrong ?

var result = (from x in db.Order
              where
                  (OrderID == 0) ? x.OrderID > 0 : x.OrderID == OrderID
                  &&
                  (string.IsNullOrEmpty(CustomerName)) ? 
                                            !string.IsNullOrEmpty(CustomerName)
                                            :
                                            x.User.Name.Contains(CustomerName)
              select x)
              .ToList();

Answer 1

I think you can not define conditional condition inside LINQ query in this way, what you can do is, for example:

var result = (from x in db.Order where
              ((OrderID == 0 && x.OrderID > 0) ||  
                (OrderID != 0 && x.OrderID == OrderID))
                  &&
                  (string.IsNullOrEmpty(CustomerName)) ? 
                                            !string.IsNullOrEmpty(CustomerName)
                                            :
                                            x.User.Name.Contains(CustomerName)....