Model.VariantFields return null when creating custom SXA rendering with variants

Question

I created custom SXA rendering with variants but Model.VariantFields return null.

my controller

public class NotificationController : VariantsController
{
    protected NotificationRepo notificationRepo
    { get; set; }

    public NotificationController()
    {

    }

    public NotificationController(NotificationRepo Repository)
    {
        notificationRepo = Repository;
    }
    protected override object GetModel()
    {
        notificationRepo = new NotificationRepo();
        return notificationRepo.GetModel();
    }
}

and the Repository code

public class NotificationRepo : ListRepository, IModelRepository, IControllerRepository, IAbstractRepository<IRenderingModelBase>
{
    public Notification NotificationItem
    {
        get
        {
            try
            {
                Notification notification = new Notification();
                string dataSourceId = RenderingContext.CurrentOrNull.Rendering.DataSource;
                Item dataSource;
                if (dataSourceId != null)
                {
                    dataSource = Sitecore.Context.Database.GetItem(dataSourceId);

                    MultilistField RelatedConetnt = dataSource.Fields["Related Content"];
                    if(RelatedConetnt != null)
                    {
                        Item NotifiactionItem = RelatedConetnt.GetItems().ToList().FirstOrDefault();

                        notification.Title = NotifiactionItem.Fields["Title"] != null ? NotifiactionItem.Fields["Title"].Value : string.Empty;
                        notification.Description = NotifiactionItem.Fields["Description"] != null ? NotifiactionItem.Fields["Description"].Value : string.Empty;
                        notification.Status = NotifiactionItem.Fields["Status"] != null ? NotifiactionItem.Fields["Status"].Value : string.Empty;
                    }

                }
                return notification;
            }
            catch(Exception ex)
            {
                Sitecore.Diagnostics.Log.Error("NotificationRepo : Error in retriving Notification data", ex);
                return null;
            }              
        }
    }
    public override IRenderingModelBase GetModel()
    {
        Notification model = new Notification();
        FillBaseProperties((object)model);
        model= this.NotificationItem;
        return (IRenderingModelBase)model;
    }
}

and my model

 public class Notification : VariantsRenderingModel
{
    public String Title { get; set; }
    public String Description { get; set; }
    public String Status { get; set; }
}

and I created simple view to test the custom rendering

@foreach (BaseVariantField variantField in Model.VariantFields)
{
    @Html.RenderingVariants().RenderVariant(variantField, Model.Item, Model.RenderingWebEditingParams, Model)
}

I get object reference to null error in the "@foreach" line where Model.VariantFields is null. When I debugged I found that Model.Item is also null.

I need to know why these properties have null??

Answer 1

There are a few things you need to fix in your code:

You are not using constructor injection in a proper way as you are manually creating your repository in GetModel() method. It should look like this:

public class NotificationController : VariantsController
{
    private NotificationRepo _repository { get; set; }

    public NotificationController(NotificationRepo repository)
    {
        _repository = repository;
    }

    protected override object GetModel()
    {
        return _repository.GetModel();
    }
}

Next... Your repository doesn't have to implement IModelRepository, IControllerRepository and IAbstractRepository<IRenderingModelBase> as you are already doing it by inheriting from ListRepository.

And the biggest problem is here:

public override IRenderingModelBase GetModel()
{
    Notification model = new Notification();
    FillBaseProperties((object)model);
    model = this.NotificationItem;
    return (IRenderingModelBase)model;
} 

What is wrong here in your opinion? You are creating your model, filling base properties and then override the whole model with mode = this.NotificationItem. Which means that everything that has been set up using FillBaseProperties method is gone...