.NET Framework 1025 Internal Data Provider Error

Question

IQueryable<Organization> query = context.Organizations; Func<Reservation, bool> predicate = r => !r.IsDeleted; query.Select(o => new { Reservations = o.Reservations.Where(predicate) }).ToList(); 

this request throws an exception "Error data provider in the environment. NET Framework 1025", but below this request is not.

 query.Select(o => new { Reservations = o.Reservations.Where( r => !r.IsDeleted) }).ToList(); 

I need to use the first, because I need to check several if statements to build the correct predicate. I know that I cannot use if statements in this case, so I pass the delegate as a parameter.

How can I fulfill the first request?

Answer 1

While the answers above are correct, note that if you try to use it after the select statement, you must explicitly call AsQueryable() , otherwise the compiler will assume that we are trying to use IEnumerable methods that expect Func and not Expression<Func> .

This was probably a problem with the original poster, because otherwise the compiler will complain most of the time when it searches for Expression<Func> , not Func .

Demo: Failed to complete the following:

 MyContext.MySet.Where(m => m.SubCollection.Select(s => s.SubItem).Any(expr)) .Load() 

While the following will work:

 MyContext.MySet.Where(m => m.SubCollection.Select(s => s.SubItem).AsQueryable().Any(expr)) .Load() 

Answer 2

After creating the bounty (rats!), I found this answer that solved my problem. (My problem is with calling .Any() , which is a little more complicated than this question ...)

In short, here is your answer:

 IQueryable<Organization> query = context.Organizations; Expression<Func<Reservation, bool>> expr = r => !r.IsDeleted; query.Select(o => new { Reservations = o.Reservations.Where(expr) }) .ToList(); 

Read the answer above to explain why you need the local variable expr , and you cannot directly refer to another method of the return type Expression<Func<Reservation, bool>> .

Answer 3

Thanks for laughing. In the end, I was on the right track.

In any case, to repeat, LINQ to Entities (thanks to Jon Skeet for correcting me when I was mixed up in my own thought process in the comments) works on Expression Trees ; it allows you to design to convert lambda expressions to SQL using QueryProvider .

Normal Func<> works well for LINQ to Objects.

So, in this case, when you use the Entity Framework, any predicate passed to EF IQueryable should be Expression<Func<>> .

Answer 4

I just experienced this problem in a different scenario.

I have a static class full of Expression predicates that I can then combine or pass into an EF request. One of them:

  public static Expression<Func<ClientEvent, bool>> ClientHasAttendeeStatus( IEnumerable<EventEnums.AttendeeStatus> statuses) { return ce => ce.Event.AttendeeStatuses .Where(a => a.ClientId == ce.Client.Id) .Select(a => a.Status.Value) .Any(statuses.Contains); } 

This caused error 1025 due to a batch call to the Contains method. The entity structure was waiting for expression and discovered a group of methods that led to an error. Converting code to use lambda (which can be implicitly applied to an expression) fixed a bug

  public static Expression<Func<ClientEvent, bool>> ClientHasAttendeeStatus( IEnumerable<EventEnums.AttendeeStatus> statuses) { return ce => ce.Event.AttendeeStatuses .Where(a => a.ClientId == ce.Client.Id) .Select(a => a.Status.Value) .Any(x => statuses.Contains(x)); } 

---

In addition, I then simplified the expression to ce => ce.Event.AttendeeStatuses.Any(a => a.ClientId == ce.Client.Id && statuses.Contains(a.Status.Value));

Answer 5

There was a similar problem. ViewModels library that looks like this:

 public class TagViewModel { public int Id { get; set; } public string Name { get; set; } public static Expression<Func<SiteTag, TagViewModel>> Select = t => new TagViewModel { Id = t.Id, Name = t.Name, }; 

It works:

 var tags = await db.Tags.Take(10).Select(TagViewModel.Select) .ToArrayAsync(); 

But this does not compile:

 var post = await db.Posts.Take(10) .Select(p => new { Post = p, Tags = p.Tags.Select(pt => pt.Tag).Select(TagViewModel.Select) }) .ToArrayAsync(); 

Because the second .Select is a mess - the first one is really called from ICollection, which is not IQueryable, so it consumes this first expression as a simple Func , not Expression<Func... This returns an IEnumerable<... as described on this page. So .AsQueryable() to the rescue:

 var post = await db.Posts.Take(10) .Select(p => new { Post = p, Tags = p.Tags.Select(pt => pt.Tag).AsQueryable() .Select(TagViewModel.Select) }) .ToArrayAsync(); 

But this creates a new, more complex problem: either I get the Internal Framework ... Error 1025, or I get the post variable with the .Post property fully loaded, but the .Tags property has an EF proxy object that seems to be used for Lazy-Loading.

The solution is to control the return type of tags by ending the use of the Anonymous class:

 public class PostViewModel { public Post Post { get; set; } public IEnumerable<TagViewModel> Tags { get; set; } 

Now select this and it all works:

 var post = await db.Posts.Take(10) .Select(p => new PostViewModel { Post = p, Tags = p.Tags.Select(pt => pt.Tag).AsQueryable() .Select(TagViewModel.Select) }) .ToArrayAsync();