Dynamic Linq.Table<TEntity> possible?

Question

Hi Guys,

I have 2 tables in a DB with very similar schemas that need to be queried in similar ways. I created a partial class for the linq entities, and then made the classes implement an interface, IEvent which defines all the properties with matching signatures that I need. All is good with that, I can cast my results to IQueryable and use the same code to work on data from more than one source. What I cannot figure out is a nice way to get the Table based on whatever "DataSource" (i.e. event table) is currently active, so currently I have this nasty switch statement that will need updating if another data source gets added and I don't like it one bit. Anyone got any smart ideas, it is late here and my brain is failing... :-S

The code goes something like this:

private IQueryable<IEvent> getEvents(IEnumerable<int> IDs)
        {
            var db = new EventDataContext();
            // activeDataSource is an enum defined elsewhere
            switch (activeDataSource)
            {
                case DataSource.Source1:
                    return db.Events1.Where(e => IDs.Contains(e.ID)).Cast<IEvent>();
                    break;
                case DataSource.Source2:
                    return db.Events2.Where(e => IDs.Contains(e.ID)).Cast<IEvent>();
                    break;
            }
        }

Answer 1

I would suggest making the method generic and using DataContext.GetTable():

private IQueryable<IEvent> getEvents<T>(IEnumerable<int> IDs)
    where T : class, IEvent
{
    var db = new EventDataContext();
    return db.GetTable<T>.Where(e => IDs.Contains(e.ID)).Cast<IEvent>();
}