10

I have a Razor Template where I need to order a list of component links by a particular field in descending order (Fields.Date). Normally when I want to loop through a list I would just do something like the below:

@foreach(dynamic item in Fields.Articles)
{
    //do something here
}

However the problem I am faced with is I need to sort the data before going into the loop and then write out the fields. Looking at the Razor Mediator documentation I can use List ComponentModel but I'm not sure what properties I can use?

@using Tridion.Extensions.Mediators.Razor.Models;

@{
    List<ComponentModel> articleList = Fields.Articles;
}

I was hoping I would be able to do something like articleList.OrderByDescending(...).

Can anyone point me in the right direction please?

  • 3
    Did you already include System.Linq? That would give you OrderByDescending and other methods like that. If that didn't work for you, could you elaborate on the issue? – Peter Kjaer Mar 21 '13 at 10:37
  • Thanks Peter, yes I have System.Linq I have tried adding articleList.OrderByDescending(x => x.Fields.Articles.Date) - can I do this considering Articles is a list of component links? I don't get any errors but to test if this works I need to write out my results. I assumed I could do this articleList.Title, articleList.Date, articleList.Body and so on? – Ibrar Hussain Mar 21 '13 at 10:44
  • 2
    Pretty sure this isn't going to work, as you can't use lambda expressions over dynamic types. – richeym Mar 21 '13 at 10:54
5

I'm assuming based on your code and comments that you are attempting to do something along the lines of:

(I modified the code a little to what the LINQ statement should look like, assuming that Fields.Articles is a list of Component Links, and each of those Components contains a field with Xml Name of "Date").

@using System.Linq;
@using Tridion.Extensions.Mediators.Razor.Models;

@{
    List<ComponentModel> articleList = Fields.Articles;
    articleList.OrderByDescending(x => x.Fields.Date);
}

@foreach (var article in articleList) { ... }

The reason that you are not seeing any error and that the list is not sorting is because OrderByDescending returns a new sorted list... it doesn't alter the original list. For your sample to work, you'd have to create one more list:

@{
    List<ComponentModel> articleList = Fields.Articles;
    var orderedList = articleList.OrderByDescending(x => x.Fields.Date);
}

You can then loop through your orderedList and it would be descending by date as expected.

A shorter version of the above using casting and creating less variables would be:

@{
    var articleList = ((List<ComponentModel>)Fields.Articles).OrderByDescending(x => x.Fields.Date);
}

Hope that helps!

  • I'm not sure that this will work - I have had trouble in the past using extension methods from System.Linq in Razor templates, without using them as a static method of Enumerable as detailed in my answer. – Ant P Mar 21 '13 at 13:40
  • Hi, do you remember the error or issue you were having? We currently do something very similar to what the OP is trying to do on my current project (sorting a bunch of articles on a page), as well as pretty extensive use of other LINQ statements. The code in my code last block is almost identical to what we are using on one of our templates. – Alex Klock Mar 21 '13 at 14:03
  • As I recall it was a simple List has no method Take on doing a list.Take(int n) after @using System.Linq. Doing Enumerable.Take(list, n) instead resolved the issue. – Ant P Mar 21 '13 at 18:34
3

I seem to recall that the Razor Mediator has problems with extension methods. This means that, in order to use OrderByDescending and other Linq extensions, you'd have to do something like:

@ {
    using System.Linq;

    List<ComponentModel> articleList =
        Enumerable.OrderByDescending(Fields.Articles, x => x.FieldToSort).ToList();
}

@foreach(var article in articleList)
{
    <h2>@article.Fields.Title</h2>
    <p>@article.Fields.Summary</h2>
    ...
}

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