Language filtered Multilist field

Recently I happened to help one of our clients to create a custom Multilist field that gives you selecting options only if item has  at least one translated version in a current content language. From content author’s point of view it makes a lot of sense. Why to give them an option that is not useful?

It’s being a while since I created a custom field that has to take into account content language selection. The main challenge for me was to retrieve that content language. I did remember that there is a property that the Content Editor (CE) sets at run-time for every field but could not recall its name. So after several minutes of browsing my code storage of all samples for all Sitecore versions, I finally found it. So, here are the properties that you need to define in your custom field if you are planning to use them afterwards:

- ItemLanauage – represents a content language selected in the CE.

- ItemID – contains the item ID the field belongs to.

- ItemVersion – contains selected item version.

- ReadOnly – indicates if field is a readonly. If it is, then it will be grayed out and not editable.

- Source – represents the source value from field definition on a data template.

- FieldID – contains the field ID.

In my example I needed only ItemLanguage property. When I put things together the code looked like this:

using Sitecore.Shell.Applications.ContentEditor;
using Sitecore.Data.Items;

namespace Sitecore.Shell.Applications.ContentEditor.CustomExtensions
{
    public class LanguageFilteredMultilist : Sitecore.Shell.Applications.ContentEditor.MultilistEx
    {
        #region Overrides

        protected override Item[] GetItems(Item current)
        {              
            Item[] items = base.GetItems(current);

            var filteredItems = items.Where(item => 
                    {
                        string lang = ItemLanguage;
                        if (!string.IsNullOrEmpty(lang))
                        {
                            var versions = Sitecore.Data.Managers.ItemManager.GetVersions(item, Sitecore.Data.Managers.LanguageManager.GetLanguage(lang, item.Database));
                            return versions.Count > 0;
                        }
                        return false;
                    }
                );   
            
            return filteredItems.ToArray<Item>();
        }

        #endregion Overrides

        // Content Editor sets this property. It has a content language from the Content Editor.
        public string ItemLanguage
        {
            get;
            set;
        }
    }
}

Simple enough isn’t it. Don’t forget to add your custom field to /App_Config/FieldTypes.config file if it’s supposed to contain references to other items. In my case it should be added since it’s a multilist. If you forget to do it, the LinkDatabase won’t update references for your field.

That’s all for now.