Sort a List by enum where enum is out of order

Question

I have a List of messages. Each message has a type.

public enum MessageType
{
    Foo = 0,
    Bar = 1,
    Boo = 2,
    Doo = 3
}

The enum

Answer 1

If you are about to get this working with Entity Framework (EF), you would have to spread out your enum in your OrderBy as such:

messageList.OrderBy(m => 
    m.MessageType == MessageType.Boo ? 0 :
    m.MessageType == MessageType.Bar ? 1 :
    m.MessageType == MessageType.Foo ? 2 :
    m.MessageType == MessageType.Doo ? 3 : 4
);

This creates a sub select with CASE WHEN, then ORDER BY on that temporary column.