Cannot Use LINQ-Method In Razor View ASP.Net

Question

I call a model in view.cshtml like this:

@model IEnumerable<Spiirit_Project.Models.Deliverable>

Then I use this LINQ-method in view.cshtml so:

@{ var a = Model.Where(p => p.deliverable_research_year_id == 169).Count(); }

When I run my project, there is error: "Value cannot be null. Parameter name: source".

my "Deliverable" Table is not null but I get this error. How to fix this error?

there is my controller:

public ActionResult CreateDeliverable(int? idResearch, int? idBaseline, int? idYear){
ViewBag.IdResearch = idResearch;
ViewBag.IdBaseline = idBaseline;
ViewBag.IdYear = idYear;
ViewBag.Year = db.Deliverable_Research_Years.Find(idYear);
ViewBag.Deliverable = db.Deliverables.ToList();

return View();
}

Your model *is* null, regardless of your claim. If you want to prove us wrong, add a screenshot of the Visual Studio debugger with the value of Model. — Camilo Terevinto, Jan 10 '19 at 02:04
Please add the controller code **to your question** (not in comments). — mjwills, Jan 10 '19 at 02:17
`return View(db.Deliverables.ToList());` - and no need to assign to `ViewBag.Deliverable`. Then have a read of https://stackoverflow.com/questions/6242810/why-is-the-view-model-null . — mjwills, Jan 10 '19 at 02:18
It is better to use `Model` than `ViewBag` - https://stackoverflow.com/questions/21716953/viewbag-vs-model-in-mvc-net — mjwills, Jan 10 '19 at 04:32
Best practice is **not** `ViewBag`. Read the link I provided. If you need multiple objects, then create your own `AghnatModel` class with multiple properties (for each of things you need). Then use `@model Spiirit_Project.Models.AghnatModel`. — mjwills, Jan 10 '19 at 04:41

score 3 · Accepted Answer · answered Jan 10 '19 at 02:51

@mjwills tell me in comment to pass in the model to the view. So I change my controller like this:

public ActionResult CreateDeliverable(int? idResearch, int? idBaseline, int? idYear){
ViewBag.IdResearch = idResearch;
ViewBag.IdBaseline = idBaseline;
ViewBag.IdYear = idYear;
ViewBag.Year = db.Deliverable_Research_Years.Find(idYear);

return View(db.Deliverables.ToList());
}

This is work correctly!

score -2 · Answer 2 · answered Jan 10 '19 at 01:59

-2

Try

@{ var a = Model?.Where(p => p.deliverable_research_year_id == 169).Count() ?? 0; }

This is assuming that deliverable_research_year_id is NOT a nullable type.

answered Jan 10 '19 at 01:59

Richard Schneider

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This assumes that the OP can use C# 6+ *and* it doesn't solve any kind of problems, it just hides a bug. – Camilo Terevinto Jan 10 '19 at 02:05

Cannot Use LINQ-Method In Razor View ASP.Net

2 Answers2