Using URL.Action inside a LINQ select method

Question

I want to create a view model that holds list items, and each item will hold the edit and delete action URL so I have the following code:

        public ActionResult Index()
        {
            AdministrationViewModel model = new AdministrationViewModel();
            using (var _context = new CamelotFaultManagementEntities())
            {
                model.FaultTypes = new ListViewModel()
                {
                    ListTitle = AdministrationStrings.FaultTypesAdministrationTab,
                    AddNewItemURL = "#",
                    AddNewItemButtonTitle = SharedStrings.Add + " " + SharedStrings.FaultType,
                    ListItems = _context.FaultTypes.Select(type => new ListItemViewModel() { 
                        ListItemID = type.FaultTypeID,
                        ListItemName = type.FaultTypeName,
                        ListItemDescription = type.FaultTypeDescription,
                        DeleteActionURL = @Url.Action("DeleteFaultType","Administration", new {FaultTypeID = type.FaultTypeID}),
                        EditActionURL = @Url.Action("EditFaultType", "Administration", new { FaultTypeID = type.FaultTypeID }),
                    }).ToList()
                };
            }
            return View("Administration",model);
        }

The problem is that I receive an error during runtime

LINQ to Entities does not recognize the method 'System.String Action(System.String, System.String, System.Object)' method, and this method cannot be translated into a store expression.

Any way to overcome this... i really don't want to start creating these URLs by myself.

Answer 1

Your problem is here:

DeleteActionURL = @Url.Action("DeleteFaultType","Administration", /*...*/),
EditActionURL = @Url.Action("EditFaultType", "Administration", /*...*/)

LINQ tries to create expression tree, which would be mapped to SQL code, but it doesn't know how to map Url.Action. One way to fix this would be change Linq to Entities to Linq to Objects, which can be done using ToList() method on your entity:

ListItems = _context.FaultTypes.ToList().Select(i => ...)