Lambda expression used inside Include is not valid

Question

My goal is to order some data coming back. I love lambda expressions, but they are failing me. The code below gets a wonderful error about not putting a lambda in an include.

public async Task<Header> GetHeader(int HeaderId)
{
    var header = await _context.Headers
            .Include(location => location.HeaderLocation)
            .Include(details => details.Details.OrderBy(x => x.FieldName).OrderBy(y => y.LineVersion).ToList())
            .Where(p => p.HeaderId == HeaderId).FirstOrDefaultAsync();
    return header;
}

The header has details, and the details need to be ordered by the property "FieldName", then by the property "LineVersion". Error I get:

Lambda expression used inside Include is not valid.

After some digging, I found a couple of ways to get around the lambda, but I am not having any luck with getting an example that has OrderBy, and my brain is failing me at the moment, and would love to get a little kick to get this working.

BTW: the code works fine when it is without the OrderBy, except that the details may not always come back in the order I need them.

Thanks in advance for the help Brad

Answer 1

I'd use a Select to get the entities with OrderBy after the Where but before FirstOrDefaultAsync() . Like this:

var header = await _context.Headers
    .Include(location => location.HeaderLocation)
    .Include(details => details.Details)
    .Where(p => p.HeaderId == HeaderId)
    .Select(header => new Header
    {
        // Assign Header values
        Location = header.Location,
        Details = header.Details.OrderBy(h => h.FieldName).OrderBy(h => h.LineVersion)
    }).FirstOrDefaultAsync();

Answer 2

On top of the other suggestion I have seen, I used the link in the comments of the original post, and got a great answer there, too. I tested it, and it works like a charm. Here is what I ended up with:

public async Task<PermitHeader> GetPermit(int HeaderId)
{
    var header = await _context.Headers
            .Include(location => location.Location)
            .Where(p => p.HeaderId == HeaderId).FirstOrDefaultAsync();
    var details = await _context.Details
            .OrderBy(ob => ob.FieldName)
            .OrderBy(ob => ob.LineVersion)
            .Where(d => d.HeaderHeaderId == HeaderId).ToListAsync();
    header.Details = Details;
    return header;
}

Thanks for a quick response!