Question

I am querying a table of Order elements with LINQ (C#). Each Order has the following fields:

- ID
- OpenDate
- PriorityID
- StatusID
- Description

The StatusID field maps to a Status table. The Status table is structured as:

- ID
- Name

I need to get all of the Order objects sorted by their Priority and Status.
I can successfully get the Order objects sorted by Priority. I’m doing this via the
following:

List<Order> orders = new List<Order>();
using (DBDataContext context = new DBDataContext())
{
  orders = (from o in context.Orders
            orderby (o.PriorityID.HasValue ? o.PriorityID : Int32.MaxValue)  ascending
            select o).ToList();
}

But my problem is factoring in the Status.

Once the order objects have been sorted by priority, I need to sort the Order objects
in the following order of Status: Cancelled, Open, In-Route, and Delivered. Significantly,
The IDs of these Status values are firmly set in a random, non-helpful order. I cannot alter them. As you can tell, I can’t sort the status by alphbetical name either. In addition, I can’t add any fields to my database. Can anyone tell me how I can solve this problem in LINQ?

Thank you!

Answer 1

I think you have solution to this by implement IComparer and use Linq to order it. Since your Status is not in numeric nor alphabet order.

public class CustomComparer : IComparer<Status>
{
     public int Compare(Status statusA, Status statusB)
     {
       if (statusA.StatusName == "Cancelled" && statusB.StatusName == "Cancelled")
       {
          return 0; // equals
       } 
       else if (statusA.StatusName == "Cancelled" && statusB.StatusName != "Cancelled")
       {
          return 1; // A > B
       }
       ....
     }
}

then

orders.OrderBy(x => x.Status, new CustomComparer())

Hope this helps.