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?
Accepted Answer
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();
Popular Answer
If you are using a generic repository and you don't know the PK at runtime, this approach can help:
public interface IGenericRepository<TEntity> where TEntity : class
{
Task<TEntity> Get(int id, string[] paths = null);
}
public class GenericRepository<TEntity> : IGenericRepository<TEntity> where TEntity : class
{
private readonly ApplicationDbContext _context;
private readonly DbSet<TEntity> _dbSet;
public GenericRepository(ApplicationDbContext context)
{
_context = context;
_dbSet = _context.Set<TEntity>();
}
public async Task<TEntity> Get(int id, string[] paths = null)
{
var model = await _dbSet.FindAsync(id);
foreach (var path in paths)
{
_context.Entry(model).Reference(path).Load();
}
return model;
}
}
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