CODEWITHSUNDEEP
c#asp.netasp.net-mvc
Mrphin
Mrphin

Reputation: 315

Check if there data for a sub Model in ViewModel

I have a ViewModel with two Models in it. In the View I want to see if there is any data in the Model:

@if (Model.MyModel1 == Empty) { do something }

But I can not figure out how to do this. When I remove this check the View works fine, I can display data from the models (when there is data) with no issues. I spent yesterday and half a day today trying a lot of different approaches I found on the web but none of them worked and none of them talked about ViewModels, only single Models, so I wonder if that is my issue. I have tried:

Model.MyModel1.Any()
Model.MyModel1.AsQueryable().Any()
Model.MyModel1[0].value1 == ""
Model.MyModel1 == null 
Model.MyModel1.IsEmptyOrNull()

More and more along these lines..

I get two types of errors, the first is when I try using a function like Model.MyModel1.Any() I get:

RuntimeBinderException: 'System.Linq.EnumerableQuery<MyThing.Models.MyModel1>' does not contain a definition for 'Any'

When I try something like Model.MyModel1[0].value1 == null I get:

RuntimeBinderException: Cannot apply indexing with [] to an expression of type 'System.Linq.EnumerableQuery<MyThing.Models.MyModle1>'

The ViewModel is:

namespace MyThing.ViewModel
{
    public class combinedModel
    {
        public IQueryable<MyModel1> MyModel1{ get; set; }
        public IQueryable<MyModel2> MyModel1{ get; set; }
    }
}

When there is no data the Controller uses this code:

        var combinedModel = new combinedModel();
        combinedModel.MyModel1 = Enumerable.Empty<MyModel1>().AsQueryable();
        combinedModel.MyModel2 = Enumerable.Empty<MyModel2>().AsQueryable();
        return View(combinedModel);

Upvotes: 0

Views: 215

Answers (2)

Mrphin
Mrphin

Reputation: 315

For my situation it seems that, as Xiaoy312 pointed out, I can not use Extension Methods in my View for some unknown reason. While I believe his answer is correct (and may be preferred way) to do this it did not work for me so I am posting what did work in case anyone else has the same issue with Extension Methods. I would read Xiaoy312 answer and comments before trying this approach.

To check if there is data in your Model, without using Extension Methods in your View, you can use: (Queryable.Count(Model.MyModel1) < 1 )

Upvotes: 0

Xiaoy312
Xiaoy312

Reputation: 14477

You were close with your first try, Model.MyModel1.Any(). However, it tests if the sequence has any element, so you want to negate that result to know if it is empty or not.

@if (!Model.MyModel1.Any()) { do something }

Upvotes: 1

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