accessing a property empties it

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Ben Palmer 176 posts 842 karma points c-trib

Apr 29, 2019 @ 12:11

Umbraco 8

Hi,

I'm using Umbraco 8 to create a new website and trying to do something really simple but having no luck.

I'm attempting to use a Surface Controller to render a list of events set up as content nodes. In my controller, I get the results but once they get passed through to my view and I try to access the events i.e. Model.Events.Any() somehow it seems to empty the property of all values.

Here's the code:

Homepage.cshtml:

@using Index.Models.PublishedContent

@inherits Umbraco.Web.Mvc.UmbracoViewPage<Homepage>

@Html.Action("RenderUpcoming", "Events")

EventsController.cs:

using Index.Models.Events;
using Index.Models.PublishedContent;
using Papermoon.Umbraco.Kupo.Core.Services.Interfaces;
using System;
using System.Linq;
using System.Web.Mvc;
using Umbraco.Web.Mvc;

namespace Index.Web.Controllers.Surface
{
    public class EventsController : SurfaceController
    {
        private readonly KupoGeneralSettings _kupoGeneralSettings;

        public EventsController(IKupoSettingsService kupoSettingsService)
        {
            _kupoGeneralSettings = kupoSettingsService.GetSettings<KupoGeneralSettings>("kupoGeneralSettings");
        }

        public ActionResult RenderUpcoming()
        {
            UpcomingEventsModel model = new UpcomingEventsModel();

            model.Title = "Upcoming Events";

            model.Events = Umbraco.ContentAtXPath("root/homepage/events/event").Select(x => new Event(x));

            model.Events = model.Events.Where(x => x.StartDate > DateTime.Now).OrderBy(x => x.StartDate).Take(3);

            model.TotalEvents = model.Events.Count();

            model.EventListingLink = _kupoGeneralSettings.EventListingLink;

            return PartialView("~/Views/Partials/Events/UpcomingEvents.cshtml", model);
        }
    }
}

In the code above, Model.Events gets filled fine but when I then do Model.TotalEvents = model.Events.Count() the result is lost. I can show this better in a video: https://i.imgur.com/rE3VAqe.gifv

It's worth noting that I've done similar in a different controller which seems to work fine.

It also seems to do the same if I do a simple check like Model.Events != null

At a total loss, any help would be massively appreciated!

Thanks,

Ben

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Rhys Hamilton 140 posts 942 karma points

Apr 29, 2019 @ 13:23

You could try something like this instead:

public ActionResult RenderUpcoming()
{
    var getAllEvents = Umbraco.ContentAtXPath("root/homepage/events/event").Select(x => new Event(x)); 
    var events = getAllEvents.Where(x => x.StartDate > DateTime.Now).OrderBy(x => x.StartDate).Take(3);

    UpcomingEventsModel model = new UpcomingEventsModel()
    {
        Title = "Upcoming Events",
        Events = events,
        TotalEvents = events.Count(),
        EventListingLink = _kupoGeneralSettings.EventListingLink
    };

    return PartialView("~/Views/Partials/Events/UpcomingEvents.cshtml", model);
}

If your events returns null, then there could be a problem in your .Where clause. By writing your code this way, you only have to set the model.Events value once and makes for slightly easier debugging.

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Ben Palmer 176 posts 842 karma points c-trib

Apr 29, 2019 @ 13:26

0

Thanks Rhys,

This will actually get abstracted off into a service but this allowed me to debug so it's probably a bit messy!

This doesn't actually fix my issue however, my where comes back with items just fine but whenever I try to do anything with it, the IEnumerable empties. I can literally be assigning the variable to the model property and by the time it gets there, it's empty.

So, using your example, when I do getAllEvents.Where..., getAllEvents is emptied even though it has values before I attempt the Where.

Thanks,

Ben

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Rhys Hamilton 140 posts 942 karma points

Apr 29, 2019 @ 13:45
0
Just so I can try set something up locally to replicate this, is getAllEvents emptied if you just do:
```
var events = getAllEvents;
```
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Ben Palmer 176 posts 842 karma points c-trib

Apr 29, 2019 @ 13:50

1

Yep correct, I've had some help over at Stack Overflow: https://stackoverflow.com/questions/55904475/c-sharp-ienumerable-emptied-once-accessed/55904526#55904526

Simple solution is to cast to a list instead of an IEnumerable, full details in the above link.

Done the IEnumerable thing millions of times in Umbraco 7 so seems like something might have actually changed in U8 to cause this.

Thanks for the help btw!

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Rhys Hamilton 140 posts 942 karma points

Apr 29, 2019 @ 13:55

1

Glad that you've found a solution and no problem at all.

If you hadn't found the solution, my next port of call would've probably have been to have a further look into the getAllEvents variable, since that was empty in events that'd pinpoint that there was likely something up with the Umbraco.ContentAtXPath("root/homepage/events/event").Select(x => new Event(x)); line.

Glad that things are resolved now though! :)

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