FindAsync and Include LINQ statements

Question

The code I have got so far works fine

public async Task<ActionResult> Details(Guid? id) {     if (id == null)     {         return new HttpStatusCodeResult(HttpStatusCode.BadRequest);     }      ItemDetailModel model = new ItemDetailModel();     model.Item = await db.Items.FindAsync(id);     if (model.Item == null)     {         return HttpNotFound();     }      return View(model); } 

But I want to include 1 table more and cannot use FindAsync

public async Task<ActionResult> Details(Guid? id) {     if (id == null)     {         return new HttpStatusCodeResult(HttpStatusCode.BadRequest);     }      ItemDetailModel model = new ItemDetailModel();     model.Item = await db.Items.Include(i=>i.ItemVerifications).FindAsync(id);      if (model.Item == null)     {         return HttpNotFound();     }                 return View(model); } 

So I am facing this error

Severity Code Description Project File Line Suppression State Error CS1061 'IQueryable' does not contain a definition for 'FindAsync' and no extension method 'FindAsync' accepting a first argument of type 'IQueryable' could be found (are you missing a using directive or an assembly reference?)

Any clue how to fix it?

Answer 1

The simplest is to use FirstOrDefaultAsync or SingleOrDefaultAsync instead:

model.Item = await db.Items.Include(i => i.ItemVerifications)     .FirstOrDefaultAsync(i => i.Id == id.Value); 

The reason you are getting the error is because Find / FindAsync methods are defined for DbSet<T>, but the result of Include is IQueryable<T>.

Another way is to combine FindAsync with explicit loading:

model.Item = await db.Items.FindAsync(id); if (model.Item == null) {     return HttpNotFound(); } await db.Entry(model.Item).Collection(i => i.ItemVerifications).LoadAsync();