Umbraco.Content is of type dynamic so you get no lambda's there. I think what you're looking for is Umbraco.TypedContent

Hi Sebastiaan,

Thanks for responding, but when I change Model with Umbraco.TypedContent(nodeId) I cannot perform a where filter on it's children.

I am using the where-statement to filter the collection. I've stripped the code to specify it some more:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Umbraco.Web.WebApi;
using Umbraco;

namespace Dts.Controllers
{
    public class ZoekController : UmbracoApiController
    {
        [System.Web.Http.HttpGet]
        public string getResult(int nodeId, string kleurgroep, string materiaal, string vorm, string formaat)
        {
            string returnValue = "test";
            string where = "Visible";

            var uniqueMateriaal = Umbraco.TypedContent(nodeId).Children.Where(where).DescendantsOrSelf("Product").Select(x => x.GetPropertyValue("materiaal")).Distinct().OrderBy(z => z);

            return returnValue;
        }
    }
}

So I want to filter the uniqeMateriaal collection to be at least visible and in the final version I will add some more filters to the where-string throught the parameters. However your hint did'nt help, I hope this makes it a little more clear. It's a first attempt at this kind of sollution through a controller, so forgive me if I've got the wrong starting point.

I am afraid it does not compile. It trips over x.IsVisible() and gives the following error:

'Umbraco.Core.Models.IPublishedContent' does not contain a definition for 'IsVisible' and no extension method 'IsVisible' accepting a first argument of type 'Umbraco.Core.Models.IPublishedContent' could be found (are you missing a using directive or an assembly reference?)

Make sure to have the following usings in your class:

using System.Linq;
using Umbraco.Web;
using Umbraco.Web.Mvc;

Especially Umbraco.Web is important as that's where the IsVisible extension method lives.

Tip: Try ReSharper out, it gives you hints about missing usings. :)

Ah that's it, thanks Sebastaan! Only one slight problem left, x => x.GetPropertyValue("materiaal") doesn't seem to work anymore. If I change it in x => x.Name it still works. Any suggestions?

Not sure what you mean? How does it not work?

Maybe try to change it to x => x.GetPropertyValue<string>("materiaal")?

Or just break it up into smaller pieces to see what goes wrong and to inspect the collection you're getting.

var products = Umbraco.TypedContent(1234).Children.Where(x => x.IsVisible()).DescendantsOrSelf("Product");
var materials = products.Select(x => x.GetPropertyValue<string>("materiaal"));
var uniqueMaterials = materials.Distinct().OrderBy(z => z);

etc.. maybe you even need to make sure materials all have the same casing: x => x.GetPropertyValue<string>("materiaal").ToLowerInvariant()

Sorry should've been a little more specific. My code is now as follows:

string where = "Visible";
var products = Umbraco.TypedContent(nodeId).DescendantsOrSelf("Product").Where(where);
var materials = products.Select(x => x.GetPropertyValue<string>("materiaal").ToLowerInvariant());
var uniqueMaterials = materials.Distinct().OrderBy(z => z);

However it breaks after declaring materials. The result view in my (VS) watch responds as a results view: 'Children could not be evaluated'. If I would change x => x.GetPropertyValue<string>("materiaal").ToLowerInvariant() into: x => x.Name I do get a result. However not the result I would like to see ;)

Yep,

The strange thins is, when I use, almost, the same code in my razor file, like:

var uniqueMateriaal = Model.Children.Where(where).DescendantsOrSelf("Product").Select(x => x.GetPropertyValue("materiaal")).Distinct().OrderBy(z => z);

It does return the result as needed. Only difference is I use Model.Children as my starting point, however I can't seem to get it to work with the same syntax.

That works too if I change "Visible" to x => x.IsVisible() :

var products = Umbraco.TypedContent(74461).Children.Where(x => x.IsVisible());

Okay well next up.. can you guess? Ah good-old-fashioned for-each:

var materials = new List<string>();
foreach (var product in products)
{
    materials.Add(product.GetPropertyValue<string>("downloadLink"));
}

What do you get for materials.Count(); if you do this?

There is nothing wrong with some old-fashioned checking. Result is, your code works, which is the most important. Allthough the question which remains is why:

Umbraco.TypedContent(nodeId).Children.Where(where).Select(x => x.GetPropertyValue("materiaal")).Distinct().OrderBy(z => z);

works, and why the following doesn not:

Umbraco.TypedContent(nodeId).Children.Where(where).DescendantsOrSelf("Product").Select(x => x.GetPropertyValue("materiaal")).Distinct().OrderBy(z => z);

Which seems to be caused by the addition of DescendantsOrSelf

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