But please don't use Umbraco.Web.Composing.Current- in most places you will use this kind of code (like an API controller, or a SurfaceController, etc). you can just access the UmbracoHelper already:

var node = Umbraco.Content(1234);

If that's not available the question is: what do you need from the UmbracoHelper exactly?

I'm guessing the most common scenario would be to query some content, in which case you can inject IUmbracoContextFactory and get an umbracoContext from it, the safe way to do that (in case the context does not exist yet) is to Ensure it exists first:

private readonly IUmbracoContextFactory _context;

public MyComponent(IUmbracoContextFactory context)
{
    _context = context;
}

public void Initialize()
{
    using (var cref = _context.EnsureUmbracoContext())
    {
        var cache = cref.UmbracoContext.ContentCache;
        var node = cache.GetById(1234);
    }

Thanks to both of you for the answers.

What I need is to query content from a custom helper class where Umbraco.Content is not available as it is in a surface controller or in a viewpage.

Umbraco.Web.Composing.Current

Solves the issue right now (though it is mentioned beeing dirty) until I get to understand DI better. Looking forward to the documentation update in general.

Best regards.

Let's get not dirty then!

The basic principle of Dependency Injection is: ask and you shall receive.

So since you're looking for Umbraco.Content, we can get there using the IUmbracoContextFactory. In your SurfaceController you can add a constructor to ask for what you need:

public class MyTestController : SurfaceController
{
    private readonly IUmbracoContextFactory _context;

    public MyTestController(IUmbracoContextFactory context)
    {
        _context = context;
    }

    // ... etc
}

Then in the methods you've created in your SurfaceController you can ask for that _context and use it:

    public ActionResult Index()
    {
        using (var cref = _context.EnsureUmbracoContext())
        {
            var cache = cref.UmbracoContext.ContentCache;
            var node = cache.GetById(1126);

            return Content(node.Name);
        }
    }

Happy to look into other things you might be needing from the UmbracoHelper and provide some samples.

This way you could eventually even start testing the logic in your controllers so you can safely refactor them at some point.

And to prove it works, the screenshot is a bit clipped but node 1126 is open there in the backoffice:

Hi again Sebastiaan

Thanks, for clarifying once again. I try to implement your solution, but it gives me an error already in the MyTestController method:

"Method must have a return type."

Yep like Bjarne points out correctly, your constructor method needs to have the same name as your class name. In my case, my class is named MyTestController so the constructor I create is public MyTestController().

Pro-tip, in Visual studio when you type ctor and then hit Enter, it will create the constructor method for you.

If the purpose is to get a specific node in the SurfaceController it should also be sufficient to access it via UmbracoHelper

public ActionResult Index()
{
    var node = Umbraco.Content(1126);

    return Content(node.Name);
}

but I guess this was to demonstrate how Dependency Injection works in v8 and how to access e.g. UmbracoContext in non Umbraco Controllers or with other dependencies?

Hi - thank you,

Now it makes sense - the constructor should be named after the class name, and it works..! - Except when I try to use _context in a static method within the class. The example here, is from my non Umbraco Controller helper class:

It seems to work if I remove readonly when defining _context and make it static also (don't know if I am beeing dirty now ;-). Like this:

  private static IUmbracoContextFactory _context;

    public ContentHelpers(IUmbracoContextFactory context)
    {
        _context = context;
    }

I could use some help with this. I have the code shown below. When I try to create a new instance of CustomUrlHelper in my template so I can use it, though, it expects me to pass it an argument of type IUmbracoContextFactory, because that's specified as a required parameter in the constructor.

How am I supposed to instantiate a custom class that uses DI?

namespace MySite.Core
{
    public class CustomUrlHelper
    {
        private readonly IUmbracoContextFactory _context;

        public CustomUrlHelper(IUmbracoContextFactory context)
        {
            _context = context;
        }

        public string GetNodeUrl(int nodeId)
        {
            IPublishedContent node = null;

            using (var cref = _context.EnsureUmbracoContext())
            {
                IPublishedContentCache cache = cref.UmbracoContext.ContentCache;
                 node = cache.GetById(nodeId);
            }

            return node.Url;
        }
    }
}

I have been playing around with V8, it's getting hard to work out what the question is about now.

If you are looking to use DI, then the test code I have below may help.

using Umbraco.Core;
using Umbraco.Core.Composing;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Web;

namespace Web.Models.Helpers
{
    public interface IHelperService
    {
        int Sum(int x, int y);
        IPublishedContent PageContentById(int pageId);
    }

    public class HelperComposer : IUserComposer
    {
        public void Compose(Composition composition)
        {
            composition.Register<IHelperService, HelperService>(Lifetime.Singleton);
        }
    }

    public class HelperService : IHelperService
    {
        private readonly IUmbracoContextFactory _contextFactory;

        public HelperService(IUmbracoContextFactory contextFactory)
        {
            _contextFactory = contextFactory;
        }
        public HelperService() { }
        public int Sum(int x, int y)
        {
            int sum = (x + y);
            return sum;
        }

        public IPublishedContent PageContentById(int pageId)
        {

            using (var cf = _contextFactory.EnsureUmbracoContext())
            {
                var cache = cf.UmbracoContext.ContentCache;
                IPublishedContent node = cache.GetById(pageId);

                return node;
            }
        }
    }
}

Now in my Controller, I have:

public class HomeController : RenderMvcController
    {
        private readonly IUmbracoContextFactory _contextFactory;
        private readonly IHelperService _helperService;

        public HomeController(IUmbracoContextFactory contextFactory, IHelperService helperService)
        {
            _contextFactory = contextFactory;
            _helperService = helperService;
        }

        public ActionResult Home()
        {
            var maths = _helperService.Sum(10, 5);
            var currentPage = CurrentPage.Id;

            var composeData = _helperService.PageContentById(currentPage);


            return View("~/Views/Home.cshtml");
        }
    }

The above returns the following

I also played about with the following

using Umbraco.Core.Models.PublishedContent;
using Umbraco.Web;

namespace Web.Models.Helpers
{
    public class PageData
    {
        public IPublishedContent PageContentById(int pageId, IUmbracoContextFactory contextFactory)
        {
            using (var cf = contextFactory.EnsureUmbracoContext())
            {
                var cache = cf.UmbracoContext.ContentCache;
                IPublishedContent node = cache.GetById(pageId);

                return node;
            }
        }
    }
}

Controller

 public ActionResult Home()
        {
            var maths = _helperService.Sum(10, 5);
            var currentPage = CurrentPage.Id;

            PageData pData = new PageData();
            var bodyText2 = pData.PageContentById(currentPage, _contextFactory);
            var htmlString = bodyText2.Value<IHtmlString>("bodyText");

            var composeData = _helperService.PageContentById(currentPage);

            var text = composeData.Value("bodyText");

            return View("~/Views/Home.cshtml");
        }

Here I'm passing the _contectFactory to my class along with the page Id and it returns the following

Hopefully, this will help someone

Playing around a bit more, say you have a layout page and you only need to get the page title and description.

For this test, I created a static class which returned a Tuple to see if it worked to return the title and description.

I then passed in the current pageId as well as UmbracoContext

var pageId = Umbraco.AssignedContentItem.Id;

    var metaInformation = MetaTitleDescriptionHelper.MetaInformationTuple(pageId,UmbracoContext);

The class is below and the codes works as expected and returns the title and description.

namespace Web.Helper.MetaHelper
{
    public static class MetaTitleDescriptionHelper
    {
        public static (string Title, string Description) MetaInformationTuple(int currentPage, UmbracoContext context)
        {
            var nodeId = context.ContentCache.GetById(currentPage);

            if (nodeId == null) return (string.Empty, string.Empty);

            string title        = nodeId.Value<string>("pageTitle", defaultValue: nodeId.Name);
            string description  = nodeId.Value<string>("pageDescription");

            return (title, description);

        }
    }
}

I just read almost the whole thread about the UmbracoContext issue and DI thing. But it is difficult for me to adapt this in my case.

I have static class, that uses the UmbracoHelper in order to retrieve a Dictionary values. This class is accessed by various Data Annotation classes. These Data Annotation classes are used as Attributes in a Model class. This model is used in a SurfaceController.

When I understand DI right, I have to pass the context from the controller to the model, somehow to the Attributes and in the Data Annotations to the static class? Maybe I am using bad architecture... but this seems quite complicated for me.

Stephan

Hi Stephan

Are you pulling the dictionary items for form validation, if yes let me know and I'll send you the code I'm using for this? The only difference I'm pulling the values from my contactDoctype

George

@George: What I am using is this: https://gist.github.com/rasmuseeg/3ca1630d45c54f485088#file-umbracodictionarydataannotations-cs

And there is a static UmbracoDictionary class that retrieves the values by key from the Dictionary

Hi Stephan

Below is how I have done it, point to note I have 2 different forms on my site, contact and blog, so I have hardcoded those values.

I have removed a lot of code, but hopefully, you can follow it

Contact View

@{
    Layout = "Layout.cshtml";
    IHelperService helperService = new HelperService();
}

@Html.Partial("~/Views/Partials/Contact/pvContact.cshtml", new ContactViewModel(helperService, UmbracoContext))

ContactViewModel - I have only added FirstName and this has PlaceHolder text and Required Helper message

public class ContactViewModel
    {
        private static IHelperService   _iHelperService;
        private const string NodeName   = "contact";
        private static UmbracoContext   _context;


        public ContactViewModel(IHelperService iHelperService, UmbracoContext context)
        {
            _iHelperService = iHelperService;
            _context = context;

        }

        public ContactViewModel() { }


        [UmbracoGetPropertyValueDisplayNameHelper("nameLabel", "contact")]
        [UmbracoGetPropertyValueRequiredHelper("nameRequired", "contact")]
        public string FromName { get; set; }
}

Validation Helper

using System.Linq;
using Umbraco.Web;
using Web.ContentHelper.ContentHelper;

namespace Web.ContentHelper.Helpers.FormValidation
{
    public static class UmbracoPropertyValidationHelper
    {
        public static string GetPropertyValueItem(string key,string nodeAlias)
        {
            var nodeId          = Umbraco.Web.Composing.Current.UmbracoHelper;
            var currentPage     = nodeId.ContentAtRoot().DescendantsOrSelfOfType(nodeAlias).First().Id;

            var data            = nodeId.Content(currentPage);

            string errorMessage = data.Value<string>(key);

            return errorMessage;

        }
    }
}

If you do not want to use UmbarcoHelper, you can also use the following

   using System.Linq;
using Umbraco.Web;
using Current = Umbraco.Web.Composing.Current;

namespace Web.ContentHelper.Helpers.FormValidation
{
    public static class UmbracoPropertyValidationHelper
    {
        public static string GetPropertyValueItem(string key,string nodeAlias)
        {
            return Current.UmbracoContext.ContentCache.GetByXPath($"//{nodeAlias}").Select(x=>x.Value<string>(key)).First();

        }
    }
}

Placeholder Helper

using System;
using System.ComponentModel;

    namespace Web.ContentHelper.Helpers.FormValidation
    {
        [AttributeUsage(AttributeTargets.Method | AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
        public class UmbracoGetPropertyValueDisplayNameHelper : DisplayNameAttribute
        {
            private readonly string _getPropertyValueKey;
            private readonly string _pageId;
            public UmbracoGetPropertyValueDisplayNameHelper(string propertyValueKey, string pageId)
            {
                _getPropertyValueKey = propertyValueKey;
                _pageId = pageId;
            }

            public override string DisplayName => UmbracoPropertyValidationHelper.GetPropertyValueItem(_getPropertyValueKey, _pageId);
        }
    }

Required Field helper

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Web.Mvc;

namespace Web.ContentHelper.Helpers.FormValidation
{
    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
    public class UmbracoGetPropertyValueRequiredHelper : RequiredAttribute, IClientValidatable
    {
        private readonly string _errorMessageKey;
        private readonly string _pageId;

        public UmbracoGetPropertyValueRequiredHelper(string errorMessageKey, string pageId)
        {
            _errorMessageKey = errorMessageKey;
            _pageId = pageId;
            ErrorMessage = UmbracoPropertyValidationHelper.GetPropertyValueItem(_errorMessageKey,_pageId);
        }



        public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        {
            ErrorMessage = UmbracoPropertyValidationHelper.GetPropertyValueItem(_errorMessageKey,_pageId);
            var error = FormatErrorMessage(metadata.DisplayName);
            var rule = new ModelClientValidationRequiredRule(error);

            yield return rule;
        }
    }
}

In my CMS contact doctype I have

nameLabel

nameRequired

Hi!

I might be late to the party here but figured I'll share my solution here.

Depending on what you need to do with the helper you can inject a "sub set" of the features from the UmbracoHelper. Ie if you're looking to query the cache use IPublishedContentQuery.

Just put it as a constructor-parameter and Umbraco will inject it for you.

private readonly IPublishedContentQuery _publishedContent;

    public MockSettingsRepository(IPublishedContentQuery publishedContent)
    {
        _publishedContent = publishedContent;
    }

Have a look here to use how the UmbracoHelper is using different interfaces internally: https://github.com/umbraco/Umbraco-CMS/blob/v8/dev/src/Umbraco.Web/UmbracoHelper.cs

I'm using the following code in Umbraco 8.1.0 but it's telling me this is deprecated now.

var cache = cref.UmbracoContext.ContentCache

Does anyone know what the new way of doing this would be?

Hi Folks,

Been struggling with this new approach. Can anyone explain how I can access UmbracoHelper in a custom HttpHandler.

With DI the constructor now has a parameter. If I setup my Custom HttpHandler I get an error regarding the constructor now containing a parameter.

Cheers,

Marc

Hi Marc,

Thanks for the reply. Was all excited about trying out the code and then no luck!!!

It looks like this may be an issue with the new V8 code however I get an error when trying this approach.

Object reference not set to an instance of an object.

[NullReferenceException: Object reference not set to an instance of an object.]
   Umbraco.Web.Runtime.<>c.<Compose>b__0_6(IFactory factory) in d:\a\1\s\src\Umbraco.Web\Runtime\WebInitialComposer.cs:116
   Umbraco.Core.FactoryExtensions.GetInstance(IFactory factory) in d:\a\1\s\src\Umbraco.Core\FactoryExtensions.cs:22
   Umbraco.Web.UmbracoHttpHandler..ctor() in d:\a\1\s\src\Umbraco.Web\UmbracoHttpHandler.cs:17
   BusinessLogic.ThemeHttpHandler..ctor() +36
   BusinessLogic.ThemeRouteHandler.GetHttpHandler(RequestContext requestContext) +70
   System.Web.Routing.UrlRoutingModule.PostResolveRequestCache(HttpContextBase context) +215
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +222
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +212
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +90

Actually may be something else I am doing wrong.

So that I can create all of this via code I have a class which inherits from IUserComposer

In the Compose Method I have:

composition.Components().Append<RegisterStyleSheetRouteComponent>();

This calls the following class:

public class RegisterStyleSheetRouteComponent : IComponent
{

    // initialize: runs once when Umbraco starts
    public void Initialize()
    {
        RouteTable.Routes.Add("ThemeStyle", new Route("theme.style", new BusinessLogic.ThemeRouteHandler()));
    }

    // terminate: runs once when Umbraco stops
    public void Terminate()
    {
    }
}

I then have the following simple class which references my HttpHandler:

public class ThemeRouteHandler : IRouteHandler
{
    public IHttpHandler GetHttpHandler(RequestContext requestContext)
    { 
        return new ThemeHttpHandler();
    }
}

This is expecting a return type of IHttpHandler. How do I change this code to work with the UmbracoHttpHandler.

Cheers,

Marc

Adding to this, it looks like there IS an issue with UmbracoHttpHandler.

I added my handler via web.config and got the same error:

<add verb="*" path="theme.style" name="HttpHandler" type="StarterKit.BusinessLogic.ThemeHttpHandler, StarterKit"/>

Hi Marc

I created a quick test httphandler in a vanilla V8 site to verify and I get the same issue...

... The thing that is null is the injected UmbracoHelper!

And if you try to use the umbracoContextFactory + ensureumbracocontext approach then this appears also to be null ..

So I've raised an issue on the tracker for it..

... apologies for the bum steer certainly seemed the recommended way....

Regards

Marc

Hi Marc,

Thanks for the heads up and majorly appreciate you looking into this for me. Umbraco 8 seems great for basic stuff but every time I try to do something a bit more complex I keep running into issues. Really itching to get going with a full on Umbraco 8 site but it looks like client sites will need to stay on Umbraco 7 for the foreseeable future.

Cheers,

Marc

Hi Marc,

Tested your solution and works perfectly. Definitely a pint I owe you if we bump into each other at future meetups.

Cheers,

Marc

I could have sworn this post was about using UmbracoHelper in a custom class outside the normal Umbraco Page or controller scope.

But the ONLY reference to using UmbracoHelper from a custom class is

var helper = Umbraco.Web.Composing.Current.UmbracoHelper; var node = helper.Content(nodeId);

What happened to the original question... How to use UmbracoHelper in a custom class

Umb 8.6.1

I find this stuff so confusing, but going on Sebs code at the top, I have this:-

using Umbraco.Core.Models.PublishedContent;
using Umbraco.Web;

namespace BSL8.Core.Helpers
{
    public class Helpers
    {
        private readonly IUmbracoContextFactory _context;

        public Helpers(IUmbracoContextFactory context)
        {
            _context = context;
        }

        public IPublishedContent GetGlobalSettingsNode()
        {               
            using (var cref = _context.EnsureUmbracoContext())
            {
                var cache = cref.UmbracoContext.ContentCache;
                var globalContent = cache.ContentSingleAtXPath("//siteWideSettings");
                return globalContent;
            }            
        }
    }
}

VS wants me to annotate the GetGlobalSettingsNode with [System.Obsolete] and cache doesn't have a "ContentSingleAtXPath". I just want a way for a C# class to get hold of the SiteWideSettings node.

Any advice appreciated.

/ Craig

Thanks Kevin,

That's cleared that up. Not sure how we get to know about these things without asking someone, so thanks.

The "Final" bit is how to call it from a static method.

    private static IPublishedContent SiteWideSettings() {           
        Helpers.Helpers helper = new Helpers.Helpers(xxxxxxx);
        IPublishedContent globalSettings = helper.GetGlobalSettingsNode();
        return globalSettings;
    }

It's asking for an IUmbracoContextFactory in place of xxxxxxx. It seems that you're always going to need an Umbraco Context when there isn't one, so what do you do? This code just appears to move the problem up the tree.

The idea I had was to have a method I could call to return the siteWideSettings node from anywhere. I guess it's not possible. Looks like I'll have to code it in place each time it's needed, which isn't very DRY. Unless I've got it completely wrong of course.

Update

Decided to re-engineer around the problem and use ICONTENT to get the SiteWideSettingsNode instead. One day I might understand DI but today's probably not that day ;)

Thanks for all the help x

Artificial example here using a starter kit and apologies if I am missing the point here (please feel free to tell me if I am :) ) but I found that if I register a service using a composer:

public interface IBlogpostService
{
    Home GetHomeNode(); // FYI - Home is a modelsbuilder model
}

public class Composer : IUserComposer
{
    public void Compose(Composition composition)
    {
        composition.Register<IBlogpostService, BlogpostService>(Lifetime.Scope);
    }
}

I can inject UmbracoHelper into that service (Is this bad? ) :

using Umbraco.Web;
using Umbraco.Web.PublishedModels;

namespace TestWeb.Web.Services.Blogpost
{

    public class BlogpostService : IBlogpostService
    {
        private readonly UmbracoHelper _umbracoHelper;

        public BlogpostService(UmbracoHelper umbracoHelper)
        {
            _umbracoHelper = umbracoHelper;
        }

        public Home GetHomeNode()
        {
            return _umbracoHelper.ContentSingleAtXPath("//" + Home.ModelTypeAlias) as Home;
        }
    }
}

NB: This only works in the context of a web request and I do recognise that GetHomeNode would be far better in an extension of UmbracoHelper but just showing that UmbracoHelper is accessible

Is this bad?

Jules

Thanks Marc,

I've been converting a V7 site to V8 and converting it's API which it uses to call external API's to create and update content. I had it all working then it came to do the scheduling. As the simple scheduledTask system (which worked absolutely fine) has been done away with I've now had to get it going with code examples kindly offered by Kevin Jump.

The problem is now with accessing the ContentService. I'm using private static IContentService contentService = Current.Services.ContentService; which only works when the API is called from a browser. When it's called from the now coded up scheduler directly it fails as there's no current. If I remove current and do as examples I've seen which just say to use Services.ContentService it complains that ContentService does not exist in the namespace, despite there being a using Umbraco.Core.Services; available.

The ContentService reference (https://our.umbraco.com/apidocs/v8/csharp/api/Umbraco.Core.Services.IContentService.html) states it's in namespace System.Dynamic.ExpandoObject but adding a using for it causes VS to complain it's not necessary.

Pretty much gone round full circle now, brain is melting so I suspect the architecture is all wrong. #stuffshouldntbethisawkward

Do we have to use DI now then to use the ContentService in a .Core C# Class (i.e. one that has nothing to do with a web request)? Even if I have absolutely no need to do any unit testing whatsoever?

I added a using for Umbraco.Core.Services.Implement but VS still said ContentService was missing a ton of arguments when used as

private static IContentService contentService = new ContentService();

I just need whatever the equivalent of this is:

 // Set up ContentService to SaveAndPublish
        private static IContentService contentService = Current.Services.ContentService;

to run when there is no Umbraco Context so I can do simple things like:-

var currentPropertyList = contentService.GetPagedChildren(propertyRootNodeID, 0, int.MaxValue, out var propertyCount); 

And then get on with adding pages, updating values, etc.

Rgds,

/ Craig

Update

As I didn't want to re-engineer 80hrs of work I've done a massive cheat and reverted my code to use current and made the new background task scheduler call via a webClient request so the code now has a request context. - Job done.

Next job is to seriously get to grips with DI before the next job!

Regards,

Craig

Hi Marc,

Thanks for your perseverance! Using Current only works if there's a request context which there isn't in this case. I've updated my last post with my "Get out!".

But as you asked.... I have...

Solution
.Core project - containing UmbracoCMS.Core and custom code
.Web project - containing a normal Umbraco site

I have Kevin's backgroundTaskScheduler in .Core as well as all my API code. Before trying to implement the backgroundTaskScheduler, i.e. just calling my API via a browser, all worked well. The API just called a few classes which pulled a couple of external API endpoints and read and wrote to Umbraco content. Where I came totally unstuck is trying to call those same classes directly from the backgroundTaskScheduler.

So my "Get Out" as indicated on my updated post, was to revert to calling the API via a URL but from within the backgroundTaskScheduler ;)

If the Scheduler kicks off again in the next 40 mins, I'm done :)

Many, many thanks.

Regards,

Craig

So i've followed the code above to create a custom class using DI.

CatalogService

public class CatalogService { private readonly IUmbracoContextFactory _context;

    public CatalogService(IUmbracoContextFactory context)
    {
        _context = context;
    }

..... }

Now within a surface controller, I want to create an instance of the CatalogService. The constructor now expects IUmbracoContextFactory. I believe that the helper is available in the surface controller.

How do I create an instance of CatalogService? Where do I get IUmbracoContextFactory to pass this into the constructor?

TIA

is working on a reply...