Member Avatar for grafic.web
grafic.web 0 Newbie Poster

Hi, is more than a week that i try to resolve this error on my app but i can't...

The problem is the following :

I have a menu and submenu table and i show this records in this mageMenu.chstml (list of menus and submenus to generate the menubar of my site) called in my _Layout.cshtml THIS IS WORKING FINE

What is not working are all the pages where the tables called are linked to the tables menu and submenu... (Example My table Magazine and the table FORUM both have a menuID and submenuID), when i run the pages with the list of this 2 tables , the app goes in error :

à System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction

Erreur  1   Impossible de convertir implicitement le type 'System.Linq.IQueryable<CollectionHair.Models.Magazine>' en 'CollectionHair.Models.Magazine'. Une conversion explicite existe (un cast est-il manquant ?)  C:\FRANCESCO\Project\CollectionHair\CollectionHair\Controllers\MagazineController.cs    26  29  Collecti

Erreur  2   'CollectionHair.Models.Magazine' ne contient pas une définition pour 'ToList' et aucune méthode d'extension 'ToList' acceptant un premier argument de type 'CollectionHair.Models.Magazine' n'a été trouvée (une directive using ou une référence d'assembly est-elle manquante ?)  C:\FRANCESCO\Project\CollectionHair\CollectionHair\Controllers\MagazineController.cs    34  25  CollectionHair

All the rest of the app working well, i mean all the other pages calling the tables that are not linked to the menu and submenu table ARE WORKING.

I'm going to put here the link to download my app and see if you understand why the error occurs :

Thanks for your help

  • 1 Contributor
  • 0 Replies
  • 204 Views

Dani AI

Generated

— Likely cause: a controller action is treating a LINQ query (a sequence) as if it were a single Magazine instance, then calling list methods on it. That produces the conversion error and the complaint that ToList doesn't exist on Magazine. The fix is to decide whether the action should return a collection or a single entity and make the types/queries match.

Example fixes (choose one):

Return a collection (materialize the query before passing to the view):

var magazines = db.Magazines
    .Where(m => m.MenuID == menuId && m.SubMenuID == submenuId)
    .Include(m => m.Menu)
    .Include(m => m.SubMenu)
    .ToList();

return View(magazines);

Return a single item (use FirstOrDefault / SingleOrDefault):

var magazine = db.Magazines
    .FirstOrDefault(m => m.Id == id);

return View(magazine);

Quick checklist and tips:

  • Confirm the controller variable type matches the query result: use var, IQueryable<Magazine>, List<Magazine>, or Magazine appropriately.
  • Avoid calling .Where(...) when a single element is expected; use FirstOrDefault / SingleOrDefault.
  • Ensure using System.Linq; (and using System.Data.Entity; when using Include) are present.
  • Match the view’s model type to what the action supplies (e.g., @model IEnumerable<Magazine> vs @model Magazine).
  • If layout/partial views load menu data and pages rely on lazy loading, either eager-load navigation properties (Include) or project into a simple ViewModel so the DB context is not required after the view starts rendering.

These changes address the type mismatch directly and will prevent the controller from trying to call collection methods on a single model instance.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.